New kind of magnetism discovered: ’Quantum Spin Liquid’
2012 12 24

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 today’s computer hard disks -- won Nobel Prizes in physics for Louis Neel in 1970 and for MIT professor emeritus Clifford Shull in 1994.

"We’re 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 don’t 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. "It’s only in the past few years that we’ve 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?
Earth’s Magnetic Field Made Quick Flip- Flop
Magnets kill cancer cells in lab
Scientist Finds Hidden Portals in Earth’s Magnetic Field
Moon Oddly Magnetic—Giant Asteroid Crash to Blame?
Quantum Entanglement Leaps Beyond Einstein --"New States of Light"
Birds use quantum theory to literally ’see’ Earth’s 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

Recent Israeli Synagogue Attack, a Possible False Flag?
2014 11 21
Dear Friends - I woke up yesterday morning to see a newspaper lying on the kitchen table with the front page proclaiming that five people were slain in an Israeli synagogue after a so-called "Palestinian attack." Some members of the media said that four people were killed, others said five, so it seems like that there was some confusion (or ...
The Michael Brown Shooting, Race Baiting for Political Power and Militarization of the Police
2014 11 21
From Youtube: The evidence clearly shows that Officer Darren Wilson was justified in shooting Michael Brown, so why is this case being hyped by the mainstream media and the leftist political establishment?
Detekt: A New Malware Detection Tool That Can Expose Illegitimate State Surveillance
2014 11 21
Recent years have seen a boom in the adoption of surveillance technology by governments around the world, including spyware that provides its purchasers the unchecked ability to target remote Internet users’ computers, to read their personal emails, listen in on private audio calls, record keystrokes and passwords, and remotely activate their computer’s camera or microphone. EFF, together with Amnesty International, ...
New UK spy chief says tech giants aid terrorism, privacy not ‘absolute right’
2014 11 21
Robert Hannigan, the new head of GCHQ The new head of Britain’s GCHQ, the UK equivalent of the NSA in the U.S., said he believes privacy is not an absolute right and that tech giants must open themselves up to intelligence agencies. “GCHQ is happy to be part of a mature debate on privacy in the digital age,” Hannigan said. “But privacy ...
LOL: Atheist Feminist Pornographer Used as Moral Authority in T-shirt Row
2014 11 21
Dr. Matt Taylor was thrust into the headlines this last week, largely for his lead role in successfully landing a spacecraft on a comet 300 million miles from earth that travels at a speed of 85,000 mph. In short, Taylor and his colleagues pulled off one of the most amazing achievements in contemporary science and space exploration, and in a ...
More News »