91福利

Spintronics with Antiferromagnets

Xavier Marti¹and Ignasi Fina²

¹Academy of Sciences of the Czech Republic, Prague, Czech Republic

²Max Planck Institute of Microstructure Physics, Halle, Germany

The bistability of distinct ordered states of spins in a magnetic material provides memory functionality. Traditionally the attention has been on ferromagnets (FMs) in which the bistability is accompanied by a macroscopic magnetic moment in the ordered state. This allows to write the FM memory by a weak external magnetic field and use the stray magnetic field of the FM for reading. However, the latest generation of magnetic random access memories demonstrates a trend in which magnetic fields are replaced by electrical means for reading and writing. This may eventually leave the sensitivity of FMs to magnetic fields as a mere weakness for data retention and the FM stray fields as an obstacle for high-density memory integration.

We report on a room-temperature bistable antiferromagnetic memory which produces negligible stray fields and is inert even in strong magnetic fields. We report microscopic theory modeling which confirms that this archetypical magnetoresistance effects discovered more than 150 years ago in FMs can be equally present in antiferromagnets (AFMs). Including AFMs greatly expands the materials base for magnetic memories and offers properties which are unparalleled in FMs.

SPINWIRE^®: the intelligent dance of cities in motion

X. Marti, J. Garces, I. Fina, T. Jungwirth – IGSresearch ()

Brief

SPINWIRE^® is the revolutionary method for deploying millions of sensors to monitor everything from street parking and traffic flow, to vehicle permits. By removing the expensive batteries, maintenance costs became negligible and nonstop high frequency readings possible

Abstract

SPINWIRE® is a new cost-effective flexible cable combining vehicle sensing, information processing, broadcasting and energy supply. A wire, 20 mm thick, is embedded on the ground and connected to any energy supply available. Each wire segment is able to wirelessly report information to parking managers and/or traffic control authorities.

The wired method naturally solves many technical limitations in the field of traffic management in realistic smart cities. First, removing the need for individual batteries and wireless components renders a massive unitary cost reduction thus allowing a superior coverage. By the same token, the plug into a wired energy supply allows a high-frequency monitoring and broadcasting thus enabling SPINWIRE® to report everything from static cars (parking) to traffic flow (density and speed detection). Finally, maintenance costs are slashed as a result of the absence of replaceable components – SPINWIRE® lasts forever, it’s just a wire.

SPINWIRE® sensors, sold in Spain and Czech Republic, are already guiding the motion of municipalities and enhancing the safety in multinational companies’ premises. Follow us at