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Primeur weekly 2014-12-22

Focus

SimScale engineering simulation platform is perfectly running in a web browser now ...

EuroFlash

RSC Group has entered in the Top10 of the world leading supercomputer vendors by TOP500 list ...

ISC High Performance introduces workshops in 2015 ...

ADVA Optical Networking transforms fiber access networks with new Access Link Monitoring solution ...

Telindus Telecom deploys ADVA Optical Networking's encryption technology to secure operator network and Cloud services ...

Institute of Aircraft Design at the University of Stuttgart selects Bright Cluster Manager for its HPC data centre ...

Imec partners with Huawei on high-bandwidth optical data link technology ...

Six new projects enabling scientific discovery to start in 2015 ...

ENTRA: Better software cuts computer energy use ...

USFlash

Cray awarded $30 million contract from the Department of Defense High Performance Computing Modernization Programme ...

High Performance Computing Modernization Programme (HPCMP) doubles capabilities ...

Ancient wisdom boosts sustainability of biotech cotton ...

Compute Canada attracts High Performance Computing talent to lead upgrades to the national advanced research platform ...

Pacific Northwest National Laboratory a major contributor to Washington state economy ...

U.S. Department of Veterans Affairs taps IBM Watson to help accelerate and enhance care delivery ...

More than 100 teams expected for ASC15, road-showed at Melbourne and Nanjing ...

Stanford team combines logic, memory to build a 'high-rise' chip ...

Tulane has one of the world's fastest computers ...

Funding ended for University of California High-Performance AstroComputing Center ...

Simulations at NERSC help illuminate attosecond laser experiment findings ...

Riding a 100G InfiniBand backbone, InfiniCortex, the Intercontinental Supercomputing Architecture, debuts in New Orleans ...

Quantum physics just got less complicated ...

Switching to spintronics ...

Lasers, multiple languages support and more with wysiwyg R34 ...

Switching to spintronics


John Heron, Cornell
17 Dec 2014 Berkeley - In a development that holds promise for future magnetic memory and logic devices, researchers with the U.S. Department of Energy (DOE)'s Lawrence Berkeley National Laboratory and Cornell University successfully used an electric field to reverse the magnetization direction in a multiferroic spintronic device at room temperature. This demonstration, which runs counter to conventional scientific wisdom, points a new way towards spintronics and smaller, faster and cheaper ways of storing and processing data.

"Our work shows that 180-degree magnetization switching in the multiferroic bismuth ferrite can be achieved at room temperature with an external electric field when the kinetics of the switching involves a two-step process", stated Ramamoorthy Ramesh, Berkeley Lab's Associate Laboratory Director for Energy Technologies, who led this research. "We exploited this multi-step switching process to demonstrate energy-efficient control of a spintronic device."

Ramamoorthy Ramesh, who also holds the Purnendu Chatterjee Endowed Chair in Energy Technologies at the University of California (UC) Berkeley, is the senior author of a paper describing this research inNature. The paper is titled "Deterministic switching of ferromagnetism at room temperature using an electric field". John Heron, now with Cornell University, is the lead and corresponding author. In addition to Ramamoorthy Ramesh and John Heron, other co-authors of theNaturepaper were James Bosse, Qing He, Ya Gao, Morgan Trassin, Linghan Ye, James Clarkson, Chen Wang, Jian Liu, Sayeef Salahuddin, Dan Ralph, Darrell Schlom, Jorge Iniguez and Bryan Huey.

Multiferroics are materials in which unique combinations of electric and magnetic properties can simultaneously coexist. They are viewed as potential cornerstones in future data storage and processing devices because their magnetism can be controlled by an electric field rather than an electric current, a distinct advantage as John Heron explained.

"The electrical currents that today's memory and logic devices rely on to generate a magnetic field are the primary source of power consumption and heating in these devices", he stated. "This has triggered significant interest in multiferroics for their potential to reduce energy consumption while also adding functionality to devices."

Nature, however, has imposed thermodynamic barriers and material symmetry constrains that theorists believed would prevent the reversal of magnetization in a multiferroic by an applied electric field. Earlier work by Ramamoorthy Ramesh and his group with bismuth ferrite, the only known thermodynamically stable room-temperature multiferroic, in which an electric field was used as on/off switch for magnetism, suggested that the kinetics of the switching process might be a way to overcome these barriers, something not considered in prior theoretical work.

"Having made devices and done on/off switching with in-plane electric fields in the past, it was a natural extension to study what happens when an out-of-plane electric field is applied", Ramamoorthy Ramesh stated.

Ramamoorthy Ramesh, John Heron and their co-authors set up a theoretical study in which an out-of-plane electric field - meaning it ran perpendicular to the orientation of the sample - was applied to bismuth ferrite films. They discovered a two-step switching process that relies on ferroelectric polarization and the rotation of the oxygen octahedral.

"The two-step switching process is key as it allows the octahedral rotation to couple to the polarization", John Heron stated. "The oxygen octahedral rotation is also critical because it is the mechanism responsible for the ferromagnetism in bismuth ferrite. Rotation of the oxygen octahedral also allows us to couple bismuth ferrite to a good ferromagnet such as cobalt-iron for use in a spintronic device."

To demonstrate the potential technological applicability of their technique, Ramamoorthy Ramesh, John Heron and their co-authors used heterostructures of bismuth ferrite and cobalt iron to fabricate a spin-valve, a spintronic device consisting of a non-magnetic material sandwiched between two ferromagnets whose electrical resistance can be readily changed. X-ray magnetic circular dichroism photoemission electron microscopy (XMCD-PEEM) images showed a clear correlation between magnetization switching and the switching from high-to-low electrical resistance in the spin-valve. The XMCD-PEEM measurements were completed at PEEM-3, an aberration corrected photo-emission electron microscope at beamline 11.0.1 of Berkeley Lab's Advanced Light Source.

"We also demonstrated that using an out-of-plane electric field to control the spin-valve consumed energy at a rate of about one order of magnitude lower than switching the device using a spin-polarized current", Ramamoorthy Ramesh stated.
Source: DOE/Lawrence Berkeley National Laboratory

Back to Table of contents

Primeur weekly 2014-12-22

Focus

SimScale engineering simulation platform is perfectly running in a web browser now ...

EuroFlash

RSC Group has entered in the Top10 of the world leading supercomputer vendors by TOP500 list ...

ISC High Performance introduces workshops in 2015 ...

ADVA Optical Networking transforms fiber access networks with new Access Link Monitoring solution ...

Telindus Telecom deploys ADVA Optical Networking's encryption technology to secure operator network and Cloud services ...

Institute of Aircraft Design at the University of Stuttgart selects Bright Cluster Manager for its HPC data centre ...

Imec partners with Huawei on high-bandwidth optical data link technology ...

Six new projects enabling scientific discovery to start in 2015 ...

ENTRA: Better software cuts computer energy use ...

USFlash

Cray awarded $30 million contract from the Department of Defense High Performance Computing Modernization Programme ...

High Performance Computing Modernization Programme (HPCMP) doubles capabilities ...

Ancient wisdom boosts sustainability of biotech cotton ...

Compute Canada attracts High Performance Computing talent to lead upgrades to the national advanced research platform ...

Pacific Northwest National Laboratory a major contributor to Washington state economy ...

U.S. Department of Veterans Affairs taps IBM Watson to help accelerate and enhance care delivery ...

More than 100 teams expected for ASC15, road-showed at Melbourne and Nanjing ...

Stanford team combines logic, memory to build a 'high-rise' chip ...

Tulane has one of the world's fastest computers ...

Funding ended for University of California High-Performance AstroComputing Center ...

Simulations at NERSC help illuminate attosecond laser experiment findings ...

Riding a 100G InfiniBand backbone, InfiniCortex, the Intercontinental Supercomputing Architecture, debuts in New Orleans ...

Quantum physics just got less complicated ...

Switching to spintronics ...

Lasers, multiple languages support and more with wysiwyg R34 ...