Science

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Fundamental observation of spin-controlled electrical conduction in metals: Ultrafast terahertz spectroscopy yields direct insight into the building block of modern magnetic memories

Modern magnetic memories, such as hard drives installed in almost every computer, can store a very large amount of information thanks to very tiny, nanoscale magnetic sensors used for memory readout. The operation of these magnetic sensors, called the spin-valves, is based on the effect of giant magnetoresistance (GMR), for which its inventors Albert Fert and Peter Gruenberg were awarded a Nobel Prize in Physics in 2007.

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Difference in conduction by electrons with opposite spins in ferromagnetic metals can be precisely resolved using terahertz waves.

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Clues to inner atomic life from subtle light-emission shifts: Hyperfine structure of light absorption by short-lived cadmium atom isotopes reveals characteristics of the nucleus that matter for high precision detection methods

Atoms absorb and emit light of various wavelengths. Physicists have long known that there are some tiny changes, or shifts, in the light that gets absorbed or emitted, due to the properties of the atomic nucleus. Now, a team of scientists has elucidated the so-called hyperfine structure of cadmium atoms. Relying on a method called laser spectroscopy, they have measured variations in the energy transition within cadmium atom - Cd in the periodic table. They studied a chain of isotopes with an odd number of neutrons ranging from 59 in 107Cd to 75 in 123Cd. From these high-precision measurements, they were able to identify the physical cause of the shift within the nucleus. These findings by Nadja Frömmgen from the Johannes Gutenberg University Mainz, in Germany, and international colleagues have now been published in EPJ D.

Two main factors influence the cadmium atom's hyperfine structure. First, electrons orbiting the nucleus create a magnetic field resulting in a force affecting the nucleus, and splitting its absorption and emission line into a number of finer lines. Second, there are influences from the way the charge is distributed within the nucleus - a quantity known as the nuclear electric quadrupole moment, which only appears for non-spherical distributions. Some nuclei are shaped like a rugby ball, a frisbee or even a pear.

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Counting stars with Gaia

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Stellar density map

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Tracking Space Weather Before It Reaches Earth

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This image of the sun from January 7, 2014, combines a picture of the sun captured by NASA’s Solar Dynamics Observatory, or SDO, with a model of the magnetic field lines using data that is also from SDO. A new model based on such data may one day help space weather forecasters better predict how eruptions from the sun will behave at Earth.

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Discovery of nanotubes offers new clues about cell-to-cell communication

When it comes to communicating with each other, some cells may be more "old school" than was previously thought.

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Discovery of nanotubes offers new clues about cell-to-cell communication.

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Nanospiked bacteria are the brightest hard X-ray emitters

In a step that overturns traditional assumptions and practice, researchers at the Tata Institute of Fundamental Research, Mumbai and Institute for Plasma Research, Gandhi Nagar have fashioned bacteria to emit intense, hard x-ray radiation.

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This image shows a 10,000 fold enhanced X-ray emission from nanoparticle doped bacteria, from plasma generated by intense ultra short infrared pulses.

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Producing spin-entangled electrons

A team from the RIKEN Center for Emergent Matter Science, along with collaborators from several Japanese institutions, have successfully produced pairs of spin-entangled electrons and demonstrated, for the first time, that these electrons remain entangled even when they are separated from one another on a chip. This research could contribute to the creation of futuristic quantum networks operating using quantum teleportation, which could allow information contained in quantum bits--qubits--to be shared between many elements on chip, a key requirement to scale up the power of a quantum computer. The ability to create non-local entangled electron pairs --known as Einstein-Podolsky-Rosen pairs --on demand has long been a dream.

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False color scanning electron microscope image of the device.
The two green spots are the quantum dots located in the gap between the two (red) electrodes.

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Measurement of Tiny Amounts of Heavy Metals in Baby Food Samples

Iranian researchers produced a nanosorbent that can adsorb and measure small amounts of heavy metals in children food samples.

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Helium 'balloons' offer new path to control complex materials

Researchers at the Department of Energy's Oak Ridge National Laboratory have developed a new method to manipulate a wide range of materials and their behavior using only a handful of helium ions.

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Inserting helium atoms (visualized as a red balloon) into a crystalline film (gold) allowed Oak Ridge National Laboratory researchers to control the material's elongation in a single direction.

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Building a better semiconductor: Research led by Michigan State University could someday lead to the development of new and improved semiconductors

In a paper published in the journal Science Advances, the scientists detailed how they developed a method to change the electronic properties of materials in a way that will more easily allow an electrical current to pass through.

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MSU researchers have found that by shooting an ultrafast laser pulse into a material, it can change its properties, a process that can lead to the development of new and improved semiconductors. The image on the right is an illustrated view of a material irradiated by the laser pulses. The one of the left is an image of the material showing subtle structural changes as a result of what’s known as photo-doping. Photo courtesy of the MSU Department of Physics and Astronomy.

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