New kind of magnetism discovered: Quantum Spin Liquid
2012-12-24 0:00

From: ScienceDaily.com

Following up on earlier theoretical predictions, MIT researchers have now demonstrated experimentally the existence of a fundamentally new kind of magnetic behavior, adding to the two previously known states of magnetism.

Ferromagnetism -- the simple magnetism of a bar magnet or compass needle -- has been known for centuries. In a second type of magnetism, antiferromagnetism, the magnetic fields of the ions within a metal or alloy cancel each other out. In both cases, the materials become magnetic only when cooled below a certain critical temperature. The prediction and discovery of antiferromagnetism -- the basis for the read heads in todays computer hard disks -- won Nobel Prizes in physics for Louis Neel in 1970 and for MIT professor emeritus Clifford Shull in 1994.

"Were showing that there is a third fundamental state for magnetism," says MIT professor of physics Young Lee. The experimental work showing the existence of this new state, called a quantum spin liquid (QSL), is reported this week in the journal Nature, with Lee as the senior author and Tianheng Han, who earned his PhD in physics at MIT earlier this year, as lead author.


MIT physicists grew this pure crystal of herbertsmithite in their laboratory. This sample, which took 10 months to grow, is 7 mm long (just over a quarter-inch) and weighs 0.2 grams.

The QSL is a solid crystal, but its magnetic state is described as liquid: Unlike the other two kinds of magnetism, the magnetic orientations of the individual particles within it fluctuate constantly, resembling the constant motion of molecules within a true liquid.

Finding the evidence

There is no static order to the magnetic orientations, known as magnetic moments, within the material, Lee explains. "But there is a strong interaction between them, and due to quantum effects, they dont lock in place," he says.

Although it is extremely difficult to measure, or prove the existence, of this exotic state, Lee says, "this is one of the strongest experimental data sets out there that [does] this. What used to just be in theorists models is a real physical system."

Philip Anderson, a leading theorist, first proposed the concept in 1987, saying that this state could be relevant to high-temperature superconductors, Lee says. "Ever since then, physicists have wanted to make such a state," he adds. "Its only in the past few years that weve made progress."

The material itself is a crystal of a mineral called herbertsmithite. Lee and his colleagues first succeeded in making a large, pure crystal of this material last year -- a process that took 10 months -- and have since been studying its properties in detail.

"This was a multidisciplinary collaboration, with physicists and chemists," Lee explains. "You need both to synthesize the material and study it with advanced physics techniques. Theorists were also crucial to this."

Through its experiments, the team made a significant discovery, Lee says: They found a state with fractionalized excitations, which had been predicted by some theorists but was a highly controversial idea. While most matter has discrete quantum states whose changes are expressed as whole numbers, this QSL material exhibits fractional quantum states. In fact, the researchers found that these excited states, called spinons, form a continuum. This observation, they say in their Nature paper, is "a remarkable first."


[...]

Read the full article at: sciencedaily.com











Related Articles
Cooking With a Magnetic Field?
Earths Magnetic Field Made Quick Flip- Flop
Magnets kill cancer cells in lab
Scientist Finds Hidden Portals in Earths Magnetic Field
Moon Oddly MagneticGiant Asteroid Crash to Blame?
Quantum Entanglement Leaps Beyond Einstein --"New States of Light"
Birds use quantum theory to literally see Earths magnetic field as they fly
For newly discovered quantum spin liquid, the beauty is in its simplicity
Scientists produce a crystal that could help unlock the mystery of high-temperature superconductors


Latest News from our Front Page

Minister of Migration attacked by asylum seeker with fire extinguisher
2015-03-27 2:12
Sweden’s Minister of Justice & Migration also known as Morgan “only 1%” Johansson, has been attacked with a fire extinguisher when he visited an asylum home for future Swedes. Regional newspaper, Kristiandstadsbladet reported that a man who had been living at the home for a couple of weeks grabbed a fire extinguisher and sprayed foam all over the minister who didn’t ...
Hollywood agents: Difficult for white actors to find work now that shows required ‘to go ethnic’
2015-03-27 1:51
According to an article by Nellie Andreeva published yesterday at Deadline Hollywood, the television landscape has shifted so much this season that white actors are finding it increasingly difficult to find roles. In addition to new hit shows with mostly minority casts — Black-ish, Empire, Fresh Off the Boat, and How to Get Away with Murder — shows that were originally ...
Congratulations Pussy Porters!
2015-03-26 18:52
Mural paid for by the government, decorates a Swedish school. On International Women’s day Julia Caesar published this chronicle in Swedish on Snaphanen which I’ve translated but prior to reading it I’d like to provide you with some background information on certain terms which are incomprehensible to non-Swedes. First and foremost “pussy porter” and “penis porter” are terms that third-wave feminists in ...
Germanwings co-pilot appears to have crashed plane deliberately – prosecutor
2015-03-26 18:08
The Germanwings co-pilot seemed to have crashed the plane deliberately, killing 150 people on board. The co-pilot wouldn’t let the captain inside the cabin, with the “intension to destroy” the jet, the French prosecutor said at a press conference. Follow RT’s live updates on investigation into Germanwings plane crash The Germanwings co-pilot was identified as Andreas Lubitz. The captain was between 30 ...
Sweden adds gender-neutral pronoun to dictionary
2015-03-25 19:38
The official dictionary of the Swedish language will introduce a gender-neutral pronoun in April, editors at the Swedish Academy have announced. “Hen” will be added to “han” (he) and “hon” (she) as one of 13,000 new words in the latest edition of the Swedish Academy’s SAOL. The pronoun is used to refer to a person without revealing their gender – either because ...
More News