New measurements of atomic-scale magnetic be- havior in iron-based superconductors by researchers at the Department of Energy's Oak Ridge National Laboratory and Vanderbilt University are challeng- ing conventional wisdom about superconductivity and magnetism.
The study published in Advanced Materi- als provides experimental evidence that local mag- netic fluctuations can influence the performance of iron-based superconductors, which transmit electric current without resistance at relatively high tempera- tures.
"In the past, everyone thought that magnetism and superconductivity could not coexist," said ORNL's Claudia Cantoni, the study's first author.
"The whole idea of superconductors is that they expel magnetic fields. But in reality things are more complicated."
Superconductivity is strongly suppressed by the presence of long-range magnetism—where atoms align their magnetic moments over large volumes —
Scientists uncover clues to role of magnetism in iron-based superconductors
“The race is on” to find a safe and scientifically interesting landing site for the Philae lander piggy- backed on ESA’s Rosetta space- craft as it swoops in ever closer to the heavily cratered Comet 67P/Churyumov-Gerasimenko since arriving two weeks agoafter a decade long chase of 6.4 billion kilometers (4 Billion miles).
Rosetta made history by becoming the first ever probe from Earth to
orbit a comet upon arrival on Aug. 6, 2014.
The probe discovered an utterly alien and bizarre icy wanderer that science team member Mark McCaughrean, of ESA’s Science Directorate, delightedly calls a
‘Scientific Disneyland.’
“It’s just astonishing,” he said during a live ESA webcast of the Aug. 6 arrival event.
Now, another audacious and histo- ry making event is on tap – Land- ing on the comet!
To enable a safe landing, Rosetta is moving in closer to the comet to gather higher resolution imaging and spectroscopic data. When Ro- setta arrived on Aug. 6, it was ini- tially orbiting at a distance of about 100 km (62 miles). As of today, carefully timed thruster firings have brought ...Read More...
Rosetta Moving Closer to Comet 67P Hunting for Philae Landing Site
Department of Physics—United Arab Emirates University
August 23, 2014 Volume 4, Issue 34Holger Sierks, OSIRIS principal investigator, dis- cusses spectacular hi res comet images returned so far by Rosetta during the Aug. 6, 2014, ESA webcast from mission control at ESOC, Darmstadt, Germa- ny. Credit: Roland Keller
Weekly news from around the world compiled by Dr. Ilias Fernini
Astronomy & Physics News
Scientists uncover clues to role of magnetism in iron-based supercon- ductors
1
Rosetta Moving Closer to Comet 67P Hunting for Philae Landing Site
1
'Cavity protection effect' helps to conserve quantum information 2 Organic photovoltaic cells of the future: Charge formation efficiency used to screen materials
2
Researchers demonstrate ultra low- field nuclear magnetic resonance using Earth's magnetic field
2
New non-metallic metamaterial enables team to 'compress' and contain light
3
Researchers find first direct evi- dence of 'spin symmetry' in atoms 3 Laser device may end pin pricks, improve quality of life for diabetics
3 Venus and Jupiter at Dawn 4 Earth’s Ozone Under Attack 4
Inside this issue:
but the ORNL study suggests that rapid fluctua- tions of local magnetic moments have a different effect. Not only does localized magnetism exist, but it is also correlated with a high critical tem- perature, the point at which the material be- comes superconducting.
"One would think for superconductivity to exist, not only the long-range order but also the local magnetic moments would have to die out," Can- toni said. "We saw instead that if ...Read More...
Oak Ridge National Laboratory scientists used scanning transmission electron microscopy to measure atomic-scale magnetic behavior in several families of iron-based super-
The electronics we use for our computers only knows two different states: zero or one.
Quantum systems on the other hand can be in different states at once, they can store a super- position of "zero" and "one". This phenome- non could be used to build ultrafast quantum computers, but there are several technological obstacles that have to be overcome first. The biggest problem is that quantum states are quickly destroyed due to interactions with the environment. At TU Wien (Vienna University of Technology), scientists have now succeed- ed in using a protection effect to enhance the stability of a particularly promising quantum system.
A Quantum Computer Made of Two Sys- tems
There are various concepts for possible quantum computers. "What we use is a hybrid system of two completely different quantum technologies", says Johannes Majer. Together with his team, he couples microwaves and atoms, investigating and building a new type of quantum memory. The theorists Dmitry Krimer and Stefan Rotter developed a theoretical model describing the complex dynamics in such hy- brid quantum systems.
In a microwave resonator, photons are created. They interact with the spin of nitrogen atoms, which are built into a diamond. The microwave resonator can be used to quickly transport quantum information.
The atomic spins in the diamond can store it – at least for a period of several hundred nanoseconds, which is long compared to the time scale on which photons move in the microwave resonator...Read More….
(Berkeley Lab) conducted a proof-of- concept NMR experiment in which a mixture of hydrocarbons and water was analyzed using a high-sensitivity magnetometer and a magnetic field comparable to that of the Earth.
The work was conducted in the NMR laboratory of Alexander Pines, one of the world's foremost NMR authorities, as part of a long-standing collaboration with physicist Dmitry Budker at the University of Califor- nia, Berkeley, along with colleagues at Earth's magnetic field, a familiar
directional indicator over long dis- tances, is routinely probed in applica- tions ranging from geology to archae- ology. Now it has provided the basis for a technique which might, one day, be used to characterize the chemical composition of fluid mix- tures in their native environments.
Researchers from the U.S. Depart- ment of Energy (DOE)'s Lawrence Berkeley National Laboratory
the National Institute of Standards and Technology (NIST). The work will be featured on the cover of Angewandte Chemie and is published in a paper titled
"Ultra-Low-Field NMR Relaxation and Diffusion Measurements Using an Opti- cal Magnetometer." The corre- sponding author is Paul Ganssle, who was a PhD stu- dent in Pines' lab at the time of the work... Read More...
'Cavity protection effect' helps to conserve quantum information
P a g e 2 V o lu m e 4 , I s s u e 3 4
as they report in Applied Physics Letters, is the combination of two types of spectroscopy.
The two types the team uses are photo-induced spectroscopy to determine the change in absorp- tion after femtosecond photo-pulse excitation, and electrochemical spectroscopy to examine the absorption change due to charge injection. "By qualitative analysis of the spectral change, we can deduce how many charges are produced by one photon—its charge formation efficiency," said Professor Yutaka Moritomo, Institute of Materi- als Science at the University of Tsukuba.
Just how significant is this? It's a huge step for- ward, said Moritomo, and the ...Read More….
Researchers demonstrate ultra low-field nuclear magnetic resonance using Earth's magnetic field
Organic photovoltaic cells of the future: Charge formation efficiency used to screen materials
Organic photovoltaic cells—a type of solar cell that uses polymeric materials to capture sun- light—show tremendous promise as energy conversion devices, thanks to key attributes such as flexibility and low-cost production.
But one giant hurdle holding back organic pho- tovoltaic technologies have been the complexity of their power conversion processes, which involve separate charge formation and transport processes.
To maneuver around this problem, a team of researchers in Japan has developed a method to determine the absolute value of the charge for- mation efficiency. The secret of their method,
A schematic illustration of Earth's magnetic field.
Credit: NASA-Credit/Copyright: Peter Reid, The University of Edinburgh
The quantum system studied at TU Wien (Vienna): a black diamond (center) contains nitrogen atoms, which are coupled to a microwave resonator. Credit: TU Wien
Researchers develop method to screen organic materials for organic photovoltaic cells by charge formation efficiency. Credit: Yutaka Morito- mo/University of Tsukuba
New non-metallic metamaterial enables team to 'compress' and contain light
The invention of fiber optics revo- lutionized the way we share infor- mation, allowing us to transmit data at volumes and speeds we'd only previously dreamed of.
ow, electrical engineering research- ers at the University of Alberta in Edmonton, Alberta, Canada are breaking another barrier, designing nano-optical cables small enough to replace the copper wiring on computer chips.
This could result in radical increas- es in computing speeds and re- duced energy use by electronic devices.
"We're already transmitting data from continent to continent us-
ing fiber optics, but the killer ap- plication is using this inside chips for interconnects—that is the Holy Grail," says Zubin Jacob, an electrical engineering professor leading the research. "What we've done is come up with a fundamen- tally new way of confining light to the nano scale."
At present, the diameter of fiber optic cables is limited to about 1/1000th of a millimeter. Cables designed by graduate student Sa- man Jahani and Jacob are 10 times smaller—small enough to replace copper wiring still used on com- puter chips. (Put into perspective, a dime is about 1 mm thick.)
Jahani and Jacob have invented a new, non- metallic met- amaterial that enables them to
"compress" and contain light waves in smaller cables without
creating heat, slowing the sig- nal or losing data. Their find- ings will be published in Optica (Aug. 20), The Opti- cal Society's (OSA) new high- impact photonics jour- nal….Read More….
superconductivity (electrical flow without re- sistance) and colossal magneto-resistance (drastic change in electrical flow in the presence of a magnetic field).
The JILA discovery, described in Science Ex- press, was made possible by the ultra-stable laser used to measure properties of the world's most precise and stable atomic clock. JILA is jointly operated by the National Institute of Standards and Technology (NIST) and the University of Colorado Boulder...Read More...
ust as diamonds with perfect symmetry may be unusually brilliant jewels, the quantum world has a symmetrical splendor of high scientific value.
Confirming this exotic quantum physics theory, JILA physicists led by theorist Ana Maria Rey and experimentalist Jun Ye have observed the first direct evidence of symmetry in the magnetic properties—or nuclear "spins"—of atoms. The advance could spin off practical benefits such as the ability to simulate and better understand exotic materials exhibiting phenomena such as
this work we hope to improve the lives of many diabetes sufferers who depend on frequent blood glucose monitoring."
In an article published June 23 in the journal Biomedical Optics Express, the researchers describe how they measured blood sugar by directing their specialized laser at a person's palm. The laser passes through the skin cells, without causing damage, and is partially absorbed by the sugar molecules in the patient's body. The re- searchers use the amount of ab- sorption to measure the level of Princeton University researchers
have developed a way to use a laser to measure people's blood sugar, and, with more work to shrink the laser system to a porta- ble size, the technique could allow diabetics to check their condition without pricking themselves to draw blood.
"We are working hard to turn engineering solutions into useful tools for people to use in their daily lives," said Claire Gmachl, the Eugene Higgins Professor of Electrical Engineering and the project's senior researcher. "With
blood sugar.
Sabbir Liakat, the paper's lead au- thor, said the team was pleasantly surprised at the accuracy of the method. Glucose monitors are re- quired to produce a blood-sugar reading within 20 percent of the patient's actual level; even an early version of the system met that standard. The current version is 84 percent accurate, Liakat said.
"It works now but we are still trying to improve it," said Liakat, a graduate student in electrical engi- neering...Read More...
P a g e 3 V o lu m e 4 , I s s u e 3 4
Researchers find first direct evidence of 'spin symmetry' in atoms
This is an illustration of symmetry in the magnetic properties - - or nuclear 'spins' -- of strontium atoms. JILA researchers observed that if two atoms have the same nuclear spin state (top), they interact weakly, and the interaction strength does not depend on which of the 10 possible nuclear spin states are involved. If the atoms have different nuclear spin states
Laser device may end pin pricks, improve quality of life for diabetics
Left: Arbitrary shaped nanoscale glass core denoted in black. The optical fields are not con- fined to the core resulting in fundamental issues of cross-talk detrimental to photonic circuits. Right:
Jahani and Jacob have invented a non-metallic metamaterial cladding which compresses the light and forces it inside the core. Credit: Saman Ja- hani and Zubin Jacob
A new system developed by Princeton researchers uses a laser to allow diabetics to check their blood sugar without pricking their skin. Members of the research team included, from left, Sabbir Liakat, a graduate student in electrical engineering; Claire Gmachl, the Eugene Higgins Professor of Electrical Engineering;
and Kevin Bors, who graduated in 2013 with a degree in electrical engineering. Credit: Frank Wojciechowski for the Office of Engineering Commu- nications
College of Science - United Arab Emirates University POB 15551
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United Arab Emirates
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by 1% a year instead of the expected 4%.
Liang’s team used several sources to piece together data from their new study, including ground-based observation and NASA’s 3-D GEOS Chemistry Climate Model.
Their work found that CC14 is still being pro- duced, somehow, and also stays in the atmos- phere for about 40% longer than thought.
They estimate worldwide emissions of about 39 kilotons per year.
The results were published late last month in Geophysical Research Letters.
Source: NASA Some bad news in the fight to protect Earth’s
ozone — one of the banned compounds that attacks this protective atmospheric layer is still being produced, somehow.
That compound is called carbon tetrachloride, which used to be common in fire extinguish- ers and dry cleaning. But those who have signed the Montreal Protocol in 1987 reported no new emissions between 2007 and 2012.
So how is it that new research found atmos- pheric emissions are persisting at 30% of peak production, even with no new emissions being reported?
“We are not supposed to be seeing this at all,”
stated lead author Qing Liang, an atmospheric scientist at NASA’s Goddard Space Flight Center in Maryland. “It is now apparent there are either unidentified industrial leakages, large emissions from contaminated sites, or un- known CCl4 sources.”
The concentrations are still declining, but only
Earth’s Ozone Under Attack Despite Banning Destructive Compound: Study
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Venus and Jupiter at Dawn
Image Credit & Copyright: Stefano De Rosa
Explanation: On Monday morning, Venus and Jupiter gathered close in dawn skies, for some separated by about half the width of a full moon. It was their closest conjunc- tion since 2000, captured here above the eastern horizon before sunrise. The serene and colorful view is from Istia beach near the city of Capoliveri on the island of Elba.
Distant lights and rolling hills are along Italy's Tuscan coast. Of course, the celestial pair soon wandered apart. Brighter Venus headed lower, toward the eastern horizon and the glare of the Sun, while Jupiter continues to rise a little higher now in the sky near dawn. The two brightest planets meet again next June 30th, in the evening twilight above the western horizon.
The ozone hole over Antarctica on Aug. 18, 2014. Purple and blue represent zones with the least ozone, while yellow and red show thicker areas. Data sources come from multi- ple NASA, European Space Agency and National Oce- anic and Atmospheric Administration satellites. Credit:
NASA
