Oakland protesters defy city order to leave

(AP) ? Hundreds of anti-Wall Street protesters defiantly remained at their campsite outside Oakland's City Hall early Saturday, despite a city order to vacate.

As the 10 p.m. time of the city's ultimatum passed Friday night, Occupy Oakland demonstrators showed no signs of departing as music blasted from the plaza. More protesters arrived with tents as midnight approached.

Earlier, city spokeswoman Karen Boyd said that Oakland gave official notice that the protesters do not have permission to remain overnight and that their encampment is breaking the law. She would not comment on what steps the city would take toward enforcing of the law. There was no indication of significant police presence early Saturday.

Boyd says that protesters can legally demonstrate at the plaza from 6 a.m. to 10 p.m.

Associated Press

Source: http://hosted2.ap.org/APDEFAULT/386c25518f464186bf7a2ac026580ce7/Article_2011-10-22-Occupy%20Wall%20Street-Oakland/id-8f7d499d0ae94feb9f148905f9510c61

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Fresh debt deal delay prompts cautious trade (Reuters)

LONDON (Reuters) ? Stocks bounced on Friday after France and Germany said a comprehensive euro zone debt deal was on its way, if a little late, although a weaker euro and rising bund futures suggested not everyone was convinced.

The long-running saga was meant to be concluded at a meeting of regional leaders on Sunday, but disagreement over the make-up of the sovereign rescue fund, the EFSF, stalled talks and sparked a selloff in riskier assets on Thursday.

A communique from French President Nicolas Sarkozy and German Chancellor Angela Merkel followed the European close, in which they said the wide-ranging plan would now be announced no later than Wednesday.

That and earnings news buoyed U.S. and Asian stocks somewhat, which in turn carried through patchily into the start of European trade on Friday, albeit with little conviction as traders wait for firm details on the plan.

"The enthusiasm, bordering on euphoria, that appeared to have swept up risk assets early in the week has now entirely evaporated and investors appear primed for a critical weekend almost expecting to be disappointed," Altium Securities said in a note.

At 0723 GMT, the MSCI world equity index (.MIWD00000PUS) was up 0.3 percent while the FTSEurofirst 300 (.FTEU3) index of leading European blue-chips was up 0.7 percent, in a bounce from its 1.4 percent selloff in the previous session.

Asian stocks (.MIAPJ0000PUS) were also slightly higher, up 0.2 percent, following modest gains for U.S. indexes overnight (.N).

MIXED VIEWS

While shares recovered some of their lost ground, currency and fixed income traders proved less amenable to the delay, extending their moves from the previous session with many investors unwilling to go long.

The euro edged higher in early trade before falling back 0.3 percent against the dollar by 0724 GMT to 1.3741. It also fell against the yen and Swiss franc. The dollar meanwhile climbed 0.1 percent against a basket of currencies (.DXY).

"The euro is all being driven by short term players with longer term investors like asset managers all holding short positions and on the sidelines," said Manuel Oliveri, currency strategist at UBS in Zurich.

Bund futures also reversed course shortly after the open, ticking lower before rising 0.1 percent to 135.53 by 0725 GMT.

"I think there is an element of disappointment," said one trader, pointing to the delay. "So today, (we are) not really expecting too much risk to be placed on by clients, instead probably some squaring of positions and taking off of risk into the weekend."

Among the major commodities, Brent crude oil was steady at around $109 a barrel, in rangebound trade ahead of the European leaders' summit, while U.S. crude oil was slightly firmer.

After heavy falls in the previous session, base metals including copper and zinc both staged a partial recovery, while gold also rose.

(Additional reporting by Anirban Nag and Ana Nicolaci da Costa in London; Editing by Catherine Evans)

Source: http://us.rd.yahoo.com/dailynews/rss/stocks/*http%3A//news.yahoo.com/s/nm/20111021/bs_nm/us_markets_global

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UK riot police clear illegal Traveler camp (AP)

CRAYS HILL, England ? British police used sledgehammers, crowbars and a cherry picker Wednesday to clear the way for the eviction of Irish Travelers from a site where they have lived illegally for a decade.

By the afternoon police said they were in control of the site, and that bailiffs were beginning to move onto the disputed property.

Essex Police said two protesters were Tasered and seven people arrested after police officers were attacked with rocks, other missiles and liquids including urine.

Residents and supporters, however, said police had used excessive force.

Evictions of Travelers, a traditionally nomadic group similar to, but ethnically distinct from, Gypsy or Roma people, are relatively common across Britain. But few are as large, or as high-profile, as Wednesday's at Dale Farm.

The police and bailiffs faced resistance from several dozen protesters who threw bricks and struggled with officers at the site, set in fields 30 miles (50 kilometers) east of London. One mobile home was set on fire as police moved in at dawn, and several protesters chained themselves to barricades with bicycle locks to slow down the evictions. Others scaled a 40-foot (12-meter) scaffolding tower.

Police moved protesters away and later used a cherry picker, or mechanized lifting platform, to reach the scaffolding platform and remove protesters who had chained themselves to the structure.

The conflict over Dale Farm has simmered since 2001, when Travelers bought and settled on a former scrap yard next to a legal Travelers' site. The legal battle dragged on for years until the Travelers lost a final appeal last week.

The local authority says it's a simple planning issue ? the 86 families lack permission to pitch homes on the land. The Travelers call it ethnic cleansing ? the latest chapter in a centuries-old story of mistrust between nomads and British society.

"I've been through a lot of evictions, but I've never seen anything like this ... they have come in and started a riot that we never wanted," said resident Kathleen McCarthy, who accused police of roughing up Travelers at the site, injuring three women. "We are being dragged out of the only homes we have in this world."

Lily Hayes, who identified herself as a human rights observer, also accused the police of using unnecessary force.

The ambulance service said one woman was taken to a hospital with minor back injuries. Five other people were treated for smoke inhalation, breathing difficulties and a nosebleed.

Authorities said the violence was coming not from residents but from their supporters ? anarchists, environmentalists and anti-capitalists who came to the site from across Europe.

"The premeditated and organized scenes of violence that we have already seen with protesters throwing rocks and bricks, threatening police with iron bars and setting fire to a caravan are shocking," said Tony Ball, leader of Basildon Council, the local authority.

He said while "no one takes any satisfaction" in the police operation, he was confident that "after 10 years of negotiations to try and find a peaceful solution to this, that what we are doing is the right thing."

There are an estimated 15,000 to 30,000 Irish Travelers in Britain, where they are recognized as a distinct ethnic minority.

Oscar-winning actress and political activist Vanessa Redgrave came to the Dale Farm Travelers' support, and the U.N. Committee on the Elimination of Racial Discrimination urged authorities to find "a peaceful and appropriate solution" to the crisis.

___________

Associated Press Writers Jill Lawless, Meera Selva and Robert Barr in London contributed to this report.

Source: http://us.rd.yahoo.com/dailynews/rss/britain/*http%3A//news.yahoo.com/s/ap/20111019/ap_on_re_eu/eu_britain_evictions

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La Russa's moves pay off, Cards win Series opener

Texas Rangers right fielder Nelson Cruz can't come up with a hit by St. Louis Cardinals' Allen Craig during the sixth inning of Game 1 of baseball's World Series Wednesday, Oct. 19, 2011, in St. Louis. (AP Photo/Charlie Riedel)

Texas Rangers right fielder Nelson Cruz can't come up with a hit by St. Louis Cardinals' Allen Craig during the sixth inning of Game 1 of baseball's World Series Wednesday, Oct. 19, 2011, in St. Louis. (AP Photo/Charlie Riedel)

St. Louis Cardinals' Allen Craig hits a RBI single off Texas Rangers' Alexi Ogando during the sixth inning of Game 1 of baseball's World Series Wednesday, Oct. 19, 2011, in St. Louis. (AP Photo/Jeff Roberson)

St. Louis Cardinals first baseman Albert Pujols makes a play on a ball hit by Texas Rangers' Michael Young during the sixth inning of Game 1 of baseball's World Series Wednesday, Oct. 19, 2011, in St. Louis. (AP Photo/Paul Sancya)

St. Louis Cardinals starting pitcher Chris Carpenter throws during the third inning of Game 1 of baseball's World Series against the Texas Rangers Wednesday, Oct. 19, 2011, in St. Louis. (AP Photo/Paul Sancya)

Texas Rangers' Mike Napoli hits a two-run home run off St. Louis Cardinals' Chris Carpenter during the fifth inning of Game 1 of baseball's World Series Wednesday, Oct. 19, 2011, in St. Louis. (AP Photo/Jeff Roberson)

(AP) ? Sometimes, it seems Tony La Russa wishes he could put a dozen more players in his dugout. Just imagine how many moves he could make then.

The St. Louis manager employed most of his roster Wednesday night, mixing and matching his way through Game 1 of the World Series and guiding the Cardinals to a 3-2 win over the Texas Rangers.

La Russa looked like a genius once again, especially when Allen Craig pinch-hit for ace Chris Carpenter and delivered a go-ahead single in the sixth inning. The slicing drive of reliever Alexi Ogando fell inches of sliding right fielder Nelson Cruz ? the opener was that tight throughout a cold, damp evening.

It was a game perfectly suited for La Russa ? lots of bunts, intentional walks and pitching changes. And in a postseason in which he's made all the right moves, the 67-year-old boss who's spent more than half his life as a big league manager was at the top of his game.

"It's going to be interesting to see how it plays out," Cardinals outfielder Lance Berkman said. "But I feel like we have to win the National League-style games if we're going to win this thing and tonight was a National League-style game ? 3-2, good pitching, good defense, timely hitting.

"I don't think that we want to get into a gorilla-ball-type series with these guys. We'll see what happens when we add the DH and go to the American League ballpark, but I think when we have the National League style and we have the advantage we have to capitalize," he said.

Texas star Michael Young could appreciate that. Sort of.

"This is real baseball. Your pitcher has to hit. More decisions come into play. A little more strategy comes into play," he said. "I enjoy this style of baseball a little more."

St. Louis used 17 of its 25 players, including five relievers.

The Cardinals even won without their Rally Squirrel. There were no sightings of the elusive critter still roaming Busch Stadium ? good thing for the rodent, too, because La Russa probably would've devised a way to catch him.

Game 2 is Thursday night, with Jaime Garcia starting for the Cards against Colby Lewis. Texas has not lost two straight games since Aug. 23-25.

The key sequences in Game 1 came in the sixth inning. In the top half, first baseman Albert Pujols helped prevent Texas from taking the lead on Carpenter's final pitch in the sixth, making a sliding stop on Young's bid for a hit.

It was still 2-all in the bottom half when Rangers starter C.J. Wilson worked around eighth-place hitter Nick Punto with a four-pitch walk that put runners at the corners with two outs.

"I know they had either Carpenter coming up or a pinch-hitter, and with Ogando warming up behind me, I have confidence that he's going to come in and get that guy out," Wilson said.

La Russa did not hesitate, pulling Carpenter and sending up Craig, a versatile player who was injured for much of the season. Texas manager Ron Washington countered by bringing in the hard-throwing Ogando.

Rather risky lately, trying to play baseball chess with La Russa. As Washington said a day earlier: "Well, I don't think I can ever live up to matching a wit with Tony La Russa."

La Russa liked Craig's chances, even though not everything was tilted in his favor.

"Cold weather game, sitting on the bench, Ogando. It's not a very good situation," La Russa said. "But he's got a history in our system, that's why we like him so much. He should have a really good career."

All the pieces in place, it was time to play ? and what followed was the play of the game.

Craig swung through two fastballs, then hit a drive toward the right field line. Cruz tried to make a sliding catch, except the ball bounced just before it reached him and thudded off his left leg for an RBI single.

"It was close. I think the dirt caught me," Cruz said.

Craig's single scored NL championship series MVP David Freese, the St. Louis-area prep star who led off with a double. Freese has hit in 11 straight postseason games.

"Man, he's tough," Craig said of Ogando. "He came right at me with fastballs, and I missed the first two. Then that last one I was trying to get the barrel on it, make the defense make a play. Fortunate, kept it fair, and Cruz made a great attempt on that. It was a great play all around."

Ahead, La Russa coaxed three scoreless innings from his deep bullpen. Jason Motte closed for his fifth save of the postseason.

This was the first time Texas had ever played in St. Louis. Yet Josh Hamilton, Cruz and the big-hitting Rangers looked a lot like the team that fizzled at the plate in last year's World Series against San Francisco.

Each team wound up with six hits. The wild-card Cardinals just did more with them.

Berkman put St. Louis ahead by chopping a two-run single in the fourth. Mike Napoli tied it with a two-run homer in the fifth.

Carpenter earned his eighth postseason win, breaking the team record he shared with Bob Gibson. Of course, all of Gibby's victories came in the World Series.

Wilson fell to 0-5 in his last seven postseason starts, including last year.

The Texas lefty recently spent 2? minutes in a Dallas cryotherapy chamber, where liquid nitrogen lowered the temperature to 295 degrees below zero, trying to speed body recovery. It was a bit warmer at the ballpark, at 49 degrees for the first pitch.

Wilson became the first pitcher to lose an All-Star game, an AL division series game, an AL championship series game and a World Series game in the same year, STATS LLC said.

"I felt like I was throwing the ball pretty well tonight, giving up a ground ball right there that scores two runs. That's unfortunate. Other than that, I minimized the damage and pitched pretty strategically to the guys I wanted to," Wilson said.

NOTES: Wilson issued two intentional walks in a game for the first time in his career. ... Rhodes, in his 20th big league season, made his World Series debut. ... This was the Cardinals' 106th World Series game, breaking a tie with the Dodgers and Giants franchises for second-most in history. The Yankees lead with 225. ... Garcia is 0-2 with a 5.74 ERA in three postseason starts. ... Lewis is 4-1 in the postseason. His loss came this year to Detroit in the ALCS. ... The team that has won the Series opener in 12 of the last 14 years has gone on to take the crown. ... This was the first AL Central vs. NL Central matchup in the Series since baseball went to six divisions in 1994. ... Young had his 35th birthday. Cardinals infielder Daniel Descalso turned 25. ... NBA All-Star Dirk Nowitzki of the champion Dallas Mavericks is set to throw out the first ball at Game 3.

Associated Press

Source: http://hosted2.ap.org/APDEFAULT/3d281c11a96b4ad082fe88aa0db04305/Article_2011-10-20-BBO-World-Series/id-3c765adaee5848118008c9f6e72a81c7

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Capital One posts 3rd-qtr profit edges up 1 pct

(AP) ? Capital One Financial Corp. on Thursday said its third-quarter profit edged up 1 percent, as it wrote more auto and commercial loans and defaults eased.

A spike in marketing and operating expenses and an increase in a reserve set aside to handle claims against the bank related to soured mortgages tempered the gains.

The McLean, Va.-based bank had net income for the quarter ended Sept. 30 of $813 million, or $1.77 per share, compared with $803 million, or $1.76 per share, in the year-ago period.

Total revenue rose 3 percent to $4.15 billion, from $4.02 billion last year.

Analysts, on average, were expecting profit of $1.68 per share on revenue of $4.04 billion, according to data provided by FactSet.

Net interest income, or money earned from deposits and loans, rose 6 percent to $3.28 billion, from $3.11 billion a year ago. Total deposits jumped nearly 8 percent to $128.32 billion. Total loans gained 3 percent to $129.95 billion.

"Overall, I think the results were pretty good," said Keefe, Bruyette & Woods analyst Sanjay Sakhrani.

The bank, best known for its ubiquitous "What's in your wallet?" advertising campaign, said U.S. credit card use rose 17 percent from the prior-year quarter. Sakhrani said the increased usage was "very strong."

Its auto finance unit wrote 40 percent more loans than last year, bringing total loans in this segment to $20.42 billion. Commercial loans also increased, rising 9 percent to $32.11 billion. CEO Richard Fairbank said during a conference call to discuss results that the growth in commercial loan commitments, which indicates future loan growth, was "even stronger."

"We believe the period of shrinking loans through the Great Recession has come to an end," Fairbank said.

Capital One wrote off $812 million in uncollectible loans, a drop of 47 percent from last year. That enabled the bank to reduce the amount it set aside to cover soured loans by 28 percent, to $622 million.

Fairbank said improvements in the performance of the bank's credit card and auto loans "have outpaced the modest and fragile economic recovery." The bank has been monitoring its outstanding credit in search of signs that recent economic difficulties will lead to another round of worsening payment performance, but said so far "we have yet to see any evidence of this."

The gains in lending were partially offset by higher marketing and operating expenses, which rose 15 percent.

Capital One also said it increased its reserve for mortgage-related claims by 3 percent to $892 million. The bank said it now believes the upper end of potential losses from such claims, which stem from mortgages that were used to back investment vehicles that have since soured, could be $1.5 billion.

The company said the pending acquisition of HSBC's U.S. credit card portfolio should close by the end of the year, pending regulatory approval. It is also still waiting for regulators to OK its purchase of ING Direct.

Capital One shares added 74 cents, or 2 percent, to close Thursday trading at $40.49. Shares rose 11 cents to $40.60 in aftermarket trading.

Associated Press

Source: http://hosted2.ap.org/APDEFAULT/f70471f764144b2fab526d39972d37b3/Article_2011-10-20-Earns-Capital%20One%20Financial/id-23a8ace3f24048259d1e78bfda478eb0

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We Absolutely Do Not Need a Best Buy-Curated App Directory [Apps]

On paper, Best Buy is now offering a new curated directory for Android and iOS apps. In reality, they're just slapping their logo over the directory already offered by Appolicious and tasking a stockboy with making a few featured picks. More »


Source: http://feeds.gawker.com/~r/gizmodo/full/~3/NTCwGBKyusY/we-absolutely-do-not-need-a-best-buy+curated-app-directory

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Which GOP candidate will become the next media star? (Reuters)

LOS ANGELES (TheWrap.com) ? Weep not for Herman Cain, Michele Bachmann, Newt Gingrich and the rest of the candidates vying for the GOP nomination.

Running for president may end up being the best business decision they ever made.

It doesn't matter that pundits expect Mitt Romney to be the Republican choice. After all, Sarah Palin's failed 2008 vice-presidential candidacy demonstrated that the loser can share in the spoils, too.

Palin has turned her national candidacy into a media empire -- churning out two books, generating as much as $100,000 for speaking gigs, and getting a reported $1 million annually as a Fox News commentator. She earned millions more from her TLC reality show series "Sarah Palin's Alaska."

In less than a year, she racked up an estimated $12 million.

Forget who's going to win the nomination -- who is most likely to become the next conservative media star?

During Tuesday night's presidential debate, the candidates continued their auditions. They once again tried to outdo one another with quips, catchy taglines and a few well-timed attacks.

"Running for president has always been a good platform, because you get free publicity," Kyle Kondik, a political analyst at the University of Virginia's Center for Politics, told TheWrap. "Someone like Herman Cain wouldn't be on TV all the time if he weren't running for president."

Chris Lehane, a Democratic consultant on the Clinton and Gore presidential campaigns, pointed out that a dozen debates with an audience of as many as 6 million people can do wonders for the right candidates.

"You have to have a degree of charisma," Lehane told TheWrap. "You have to be able to connect with viewers on television, but if you have something that distinguishes yourself from the group, you can really leverage your brand."

So far, America, particularly a conservative swath of it, is buying what Cain is selling. Political pundits and media analysts say that the witty and spirited former head of Godfather's Pizza has the best chance to cash in after the votes are cast and the concession speech is delivered.

"Cain has the charisma to sustain a second act," Felicia Knight, president of the media strategy firm Knight Vision International, told TheWrap. "In order to have a second act, you have to have some kind of personality, whether it's being abrasive or humorous, that draws people to you. People can be smart enough or bright enough to be commander in chief and not have that."

All the television time has done wonders for sales of Cain's autobiography "This is Herman Cain!," which has shot up the bestseller charts since he threw his hat in the ring.

Indeed, it's led to charges that Cain is more interested in moving copies of his life story than he is in rounding up delegates. Cain has been spending more time at book signings in states without early primaries than he has been lining up delegates in Iowa, his critics allege.

Bachmann, whose good looks and Bible-thumping have already led to comparisons with a certain former Alaska governor, could also conceivably start her own cottage industry if she decides not to run for Congress again. She has the same passionate conservative base as Palin and a similar penchant for headline-grabbing remarks.

There are some who suspect, however, that Bachmann's star fizzled out last summer when she was topping polls. A litany of political gaffes, such as claiming the Founding Fathers ended slavery, may have tarnished the Bachmann brand before the Minnesota congresswoman was ready to cash in.

"She doesn't have the star power that Palin does," Kondik said. "If you look at Bachmann's trajectory, she shot up, but she shot back down again. She got good publicity, but her stock fell the more people got to know her."

Nipping at Bachmann and Cain's heels is Newt Gingrich, a man with more than 20 books to his name and a previous stint as a Fox News commentator. It's possible that his candidacy will keep those royalties and speakers fees rolling.

By running for president, he's keeping the brand relevant. Some believe Palin attempted to do the same with her "is she or isn't she" presidential candidacy.

Beyond the big three, the picture becomes somewhat murkier. Analysts tell TheWrap that at this point, it seems more likely that Romney, Jon Hunstman, Rick Perry and Ron Paul will choose to remain in public life by working in government or in a foundation, instead of chasing fame.

Though Rick Santorum was previously a Fox News contributor, he may lack the sizzle to become a bigger cable news star, even if he has the desire.

Donald Trump didn't even file his papers, yet he reaped the benefits from his presidential flirtation. He cut bait before primary season officially started, raising his media profile -- and boosting ratings for "The Celebrity Apprentice" -- without having to do something as unseemly as glad-hand in Des Moines or chomp down on a corn dog.

Other candidates from both parties have used failed campaigns to further media careers. Mike Huckabee transformed his runner-up status into a Fox News show and 2004 Democratic presidential candidate Al Sharpton has hosting duties over at rival MSNBC.

In fact, the line of campaign losers who have become media winners stretches back to Pat Buchanan, who went from giving George H.W. Bush agita in a 1991 primary challenge to offering his insight on the days political news for CNN and later

MSNBC.

But Palin, and the millions she racked up, took it to a whole new level.

"She really became the queen of all media," Stuart Schwartz, a former senior producer at ABC News, told TheWrap.

Schwartz said that the kind of cross-platform dominance Palin achieved, and that other Republican candidates are gunning for, couldn't have taken place before the cable landscape became fractured.

"This sort of thing didn't happen when you had three networks, but there are so many outlets and so many shows for people to bloviate on endlessly," Schwartz said.

And voters are watching. The presidential debates have been getting good ratings on the various networks that have been airing them.

"GOP debates are great television," Colby Hall, managing editor of Mediaite, told TheWrap. "They are a reality show. All of these candidates are really interesting and fascinating characters, including Ron Paul. It's not just policy dorks that love to watch these things now. They have their own weird drama."

(Lucas Shaw contributed to this report)

Source: http://us.rd.yahoo.com/dailynews/rss/tv/*http%3A//news.yahoo.com/s/nm/20111019/tv_nm/us_conservatives

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Impurity atoms introduce waves of disorder in exotic electronic material

[ Back to EurekAlert! ] Public release date: 17-Oct-2011
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Contact: Karen McNulty Walsh
kmcnulty@bnl.gov
631-344-8350
DOE/Brookhaven National Laboratory

Sophisticated electron-imaging technique reveals widespread "destruction," offering clues to how material works as a superconductor

UPTON, NY - It's a basic technique learned early, maybe even before kindergarten: Pulling things apart - from toy cars to complicated electronic materials - can reveal a lot about how they work. "That's one way physicists study the things that they love; they do it by destroying them," said Samus Davis, a physicist at the U.S. Department of Energy's (DOE) Brookhaven National Laboratory and the J.G. White Distinguished Professor of Physical Sciences at Cornell University.

Davis and colleagues recently turned this destructive approach - and a sophisticated tool for "seeing" the effects - on a material they've been studying for its own intrinsic beauty, and for the clues it may offer about superconductivity, the ability of some materials to carry electric current with no resistance. The findings, published in the Proceedings of the National Academy of Sciences the week of October 17, 2011, reveal how substituting just a few atoms can cause widespread disruption of the delicate interactions that give the material its unique properties, including superconductivity.

The material, a compound of uranium, ruthenium, and silicon, is known as a "heavy-fermion" system. "It's a system where the electrons zooming through the material stop periodically to interact with electrons localized on the uranium atoms that make up the lattice, or framework of the crystal," Davis said. These stop-and-go magnetic interactions slow down the electrons, making them appear as if they've taken on extra mass, but also contribute to the material's superconductivity.

In 2010*, Davis and a group of collaborators visualized these heavy fermions for the first time using a technique developed by Davis, known as spectroscopic imaging scanning tunneling microscopy (SI-STM), which measures the wavelength of electrons of the material in relation to their energy.

The idea of the present study was to "destroy" the heavy fermion system by substituting thorium for some of the uranium atoms. Thorium, unlike uranium, is non-magnetic, so in theory, the electrons should be able to move freely around the thorium atoms, instead of stopping for the brief magnetic encounters they have at each uranium atom. These areas where the electrons should flow freely are known as "Kondo holes," named for the physicist who first described the scattering of conductive electrons due to magnetic impurities.

Free-flowing electrons might sound like a good thing if you want a material that can carry current with no resistance. But Kondo holes turn out to be quite destructive to superconductivity. By visualizing the behavior of electrons around Kondo holes for the first time, Davis' current research helps to explain why.

"There have been beautiful theories that predict the effects of Kondo holes, but no one knew how to look at the behavior of the electrons, until now," Davis said.

Working with thorium-doped samples made by physicist Graeme Luke at McMaster University in Ontario, Davis' team used SI-STM to visualize the electron behavior.

"First we identified the sites of the thorium atoms in the lattice, then we looked at the quantum mechanical wave functions of the electrons surrounding those sites," Davis said.

The SI-STM measurements bore out many of the theoretical predictions, including the idea proposed just last year by physicist Dirk Morr of the University of Illinois that the electron waves would oscillate wildly around the Kondo holes, like ocean waves hitting a lighthouse.

"Our measurements revealed waves of disturbance in the 'quantum glue' holding the heavy fermions together," Davis said.

So, by destroying the heavy fermions - which must pair up for the material to act as a superconductor - the Kondo holes disrupt the material's superconductivity.

Davis' visualization technique also reveals how just a few Kondo holes can cause such widespread destruction: "The waves of disturbance surrounding each thorium atom are like the ripples that emanate from raindrops suddenly hitting a still pond on a calm day," he said. "And like those ripples, the electronic disturbances travel out quite a distance, interacting with one another. So it takes a tiny number of these impurities to make a lot of disorder."

What the scientists learn by studying the exotic heavy fermion system may also pertain to the mechanism of other superconductors that can operate at warmer temperatures.

"The interactions in high-temperature superconductors are horribly complicated," Davis said. "But understanding the magnetic mechanism that leads to pairing in heavy fermion superconductors - and how it can so easily be disrupted - may offer clues to how similar magnetic interactions might contribute to superconductivity in other materials."

###

This research was supported by the DOE's Office of Science, the Natural Sciences and Engineering Research Council of Canada, and the Canadian Institute for Advanced Research. Additional collaborators included Mohammad Hamidian and Ines Firmo of Brookhaven Lab and Cornell, and Andy Schmidt now at the University of California, Berkeley.

RELATED LINKS:

First Images of Heavy Electrons in Action: http://www.bnl.gov/bnlweb/pubaf/pr/PR_display.asp?prID=1130

One of ten national laboratories overseen and primarily funded by the Office of Science of the U.S. Department of Energy (DOE), Brookhaven National Laboratory conducts research in the physical, biomedical, and environmental sciences, as well as in energy technologies and national security. Brookhaven Lab also builds and operates major scientific facilities available to university, industry and government researchers. Brookhaven is operated and managed for DOE's Office of Science by Brookhaven Science Associates, a limited-liability company founded by the Research Foundation of State University of New York on behalf of Stony Brook University, the largest academic user of Laboratory facilities, and Battelle, a nonprofit, applied science and technology organization. Visit Brookhaven Lab's electronic newsroom for links, news archives, graphics, and more at http://www.bnl.gov/newsroom , or follow Brookhaven Lab on Twitter, http://twitter.com/BrookhavenLab .


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[ Back to EurekAlert! ] Public release date: 17-Oct-2011
[ | E-mail | Share Share ]

Contact: Karen McNulty Walsh
kmcnulty@bnl.gov
631-344-8350
DOE/Brookhaven National Laboratory

Sophisticated electron-imaging technique reveals widespread "destruction," offering clues to how material works as a superconductor

UPTON, NY - It's a basic technique learned early, maybe even before kindergarten: Pulling things apart - from toy cars to complicated electronic materials - can reveal a lot about how they work. "That's one way physicists study the things that they love; they do it by destroying them," said Samus Davis, a physicist at the U.S. Department of Energy's (DOE) Brookhaven National Laboratory and the J.G. White Distinguished Professor of Physical Sciences at Cornell University.

Davis and colleagues recently turned this destructive approach - and a sophisticated tool for "seeing" the effects - on a material they've been studying for its own intrinsic beauty, and for the clues it may offer about superconductivity, the ability of some materials to carry electric current with no resistance. The findings, published in the Proceedings of the National Academy of Sciences the week of October 17, 2011, reveal how substituting just a few atoms can cause widespread disruption of the delicate interactions that give the material its unique properties, including superconductivity.

The material, a compound of uranium, ruthenium, and silicon, is known as a "heavy-fermion" system. "It's a system where the electrons zooming through the material stop periodically to interact with electrons localized on the uranium atoms that make up the lattice, or framework of the crystal," Davis said. These stop-and-go magnetic interactions slow down the electrons, making them appear as if they've taken on extra mass, but also contribute to the material's superconductivity.

In 2010*, Davis and a group of collaborators visualized these heavy fermions for the first time using a technique developed by Davis, known as spectroscopic imaging scanning tunneling microscopy (SI-STM), which measures the wavelength of electrons of the material in relation to their energy.

The idea of the present study was to "destroy" the heavy fermion system by substituting thorium for some of the uranium atoms. Thorium, unlike uranium, is non-magnetic, so in theory, the electrons should be able to move freely around the thorium atoms, instead of stopping for the brief magnetic encounters they have at each uranium atom. These areas where the electrons should flow freely are known as "Kondo holes," named for the physicist who first described the scattering of conductive electrons due to magnetic impurities.

Free-flowing electrons might sound like a good thing if you want a material that can carry current with no resistance. But Kondo holes turn out to be quite destructive to superconductivity. By visualizing the behavior of electrons around Kondo holes for the first time, Davis' current research helps to explain why.

"There have been beautiful theories that predict the effects of Kondo holes, but no one knew how to look at the behavior of the electrons, until now," Davis said.

Working with thorium-doped samples made by physicist Graeme Luke at McMaster University in Ontario, Davis' team used SI-STM to visualize the electron behavior.

"First we identified the sites of the thorium atoms in the lattice, then we looked at the quantum mechanical wave functions of the electrons surrounding those sites," Davis said.

The SI-STM measurements bore out many of the theoretical predictions, including the idea proposed just last year by physicist Dirk Morr of the University of Illinois that the electron waves would oscillate wildly around the Kondo holes, like ocean waves hitting a lighthouse.

"Our measurements revealed waves of disturbance in the 'quantum glue' holding the heavy fermions together," Davis said.

So, by destroying the heavy fermions - which must pair up for the material to act as a superconductor - the Kondo holes disrupt the material's superconductivity.

Davis' visualization technique also reveals how just a few Kondo holes can cause such widespread destruction: "The waves of disturbance surrounding each thorium atom are like the ripples that emanate from raindrops suddenly hitting a still pond on a calm day," he said. "And like those ripples, the electronic disturbances travel out quite a distance, interacting with one another. So it takes a tiny number of these impurities to make a lot of disorder."

What the scientists learn by studying the exotic heavy fermion system may also pertain to the mechanism of other superconductors that can operate at warmer temperatures.

"The interactions in high-temperature superconductors are horribly complicated," Davis said. "But understanding the magnetic mechanism that leads to pairing in heavy fermion superconductors - and how it can so easily be disrupted - may offer clues to how similar magnetic interactions might contribute to superconductivity in other materials."

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This research was supported by the DOE's Office of Science, the Natural Sciences and Engineering Research Council of Canada, and the Canadian Institute for Advanced Research. Additional collaborators included Mohammad Hamidian and Ines Firmo of Brookhaven Lab and Cornell, and Andy Schmidt now at the University of California, Berkeley.

RELATED LINKS:

First Images of Heavy Electrons in Action: http://www.bnl.gov/bnlweb/pubaf/pr/PR_display.asp?prID=1130

One of ten national laboratories overseen and primarily funded by the Office of Science of the U.S. Department of Energy (DOE), Brookhaven National Laboratory conducts research in the physical, biomedical, and environmental sciences, as well as in energy technologies and national security. Brookhaven Lab also builds and operates major scientific facilities available to university, industry and government researchers. Brookhaven is operated and managed for DOE's Office of Science by Brookhaven Science Associates, a limited-liability company founded by the Research Foundation of State University of New York on behalf of Stony Brook University, the largest academic user of Laboratory facilities, and Battelle, a nonprofit, applied science and technology organization. Visit Brookhaven Lab's electronic newsroom for links, news archives, graphics, and more at http://www.bnl.gov/newsroom , or follow Brookhaven Lab on Twitter, http://twitter.com/BrookhavenLab .


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Source: http://www.eurekalert.org/pub_releases/2011-10/dnl-iai101711.php

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