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Walther-Meißner-Institut (WMI), Bayerische Akademie der Wissenschaften
Chair for Technical Physics (E23), Technische Universität München

Spin Hall Magnetoresistance

BADW

May 13, 2013



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In a collaboration with partners from Tohoku University (Japan) and Delft University of Technology (The Netherlands), researchers from the Walther-Meißner-Institut (WMI), Bayerische Akademie der Wissenschaften and Technische Universität München, discovered a new type of magnetoresistance, resulting from spin-dependent scattering at a metal-magnet interface. This novel effect may potentially be used to study the magnetization in insulating magnets or to develop new spintronic devices.


SpinCaTlogoMagnetoresistance is an important material property that is utilized in electronic compasses, hard disk drives, biosensors, and microelectromechanical systems (MEMS). In normal (nonmagnetic) conductors, magnetoresistance is a variation of the resistance that occurs when an external magnetic field influences how electrons flow through the material. In magnetic conductors, the magnetoresistance depends on the magnetization direction. In Physical Review Letters, a team of researcher from Walther-Meißner-Institut, Tohoku University (Sendai, Japan) and Delft University of Technology (The Netherlands) reports on a new kind of magnetoresistance in a system with an insulating magnet. Meanwhile, the results are independently corroborated and shown to also exist in other materials by a group at CEA Saclay (Atomic Energy Commission), France The discovery may open new applications of insulator spintronics, devices that utilize spin currents in insulating magnets. The new type of magnetoresistance is coined spin Hall magnetoresistance (SMR) and joins a long list of similar spin-dependent effects that have powered a wide range of applications.

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Journal reference

Spin Hall Magnetoresistance Induced by a Nonequilibrium Proximity Effect
H. Nakayama, M. Althammer, Y.-T. Chen, K. Uchida, Y. Kajiwara, D. Kikuchi, T. Ohtani, S. Geprägs, M. Opel, S. Takahashi, R. Gross, G. E. W. Bauer, S. T. B. Goennenwein, and E. Saitoh
Physical Review Letters 110, 206601 (2013), 10.1103/PhysRevLett.110.206601.

Acknowledgements:

The work at Tohoku University was supported by CREST-JST ‘‘Creation of Nanosystems with Novel Functions through Process Integration,’’ Japan, PRESTOJST ‘‘Phase Interfaces for Highly Efficient Energy Utilization,’’ Japan, Grant-in-Aid for JSPS Fellows from JSPS, Japan, a Grant-in-Aid for Scientific Research A (24244051) from MEXT, Japan, a Grant-in-Aid for Scientific Research C (25400337) from MEXT, Japan, a Grant-in-Aid for Research Activity Start-up 24860003) from MEXT, Japan, LC-IMR of Tohoku University, and the Murata Science Foundation. The work at the Walther- Meißner-Institut and TU Delft was supported by the Deutsche Forschungsgemeinschaft (DFG) through priority programme SPP 1538 ‘‘Spin-Caloric Transport,’’ project GO 944/4. G. E.W. B. acknowledges support from the Dutch FOM Foundation and EC-Project MACALO. H. N. and M. A. contributed equally to this work.

Contact:

Dr. Sebastian T. B. Gönnenweinl
Walther-Meißner-Institut, Bayerische Akademie der Wissenschaften
und Physik-Department, TU München
Tel.: +49 (0)89 / 289 –14311
E-Mail: Sebastian.Goennenwein@wmi.badw.de
Web: http://www.wmi.badw-muenchen.de/

Prof. Dr. Rudolf Gross
Walther-Meißner-Institut, Bayerische Akademie der Wissenschaften
und Physik-Department, TU München
Tel.: +49 (0)89 / 289 –14201
E-Mail: Rudolf.Gross@wmi.badw.de
Web: http://www.wmi.badw-muenchen.de/

SMR_Scheme

Spin Hall magnetoresistance occurs in hybrid systems combining a normal metal (blue) and a magnetic insulator (green). When a charge current (Icharge) flows through the metal, it generates a perpendicular spin current (Ispin), which results in an accumulation of spin at the metal-insulator interface. If the insulator’s magnetization (M) points perpendicular to the edge spin accumulation, then some of spins can transfer from metal to insulator. The net effect of this spin transfer is an increase in the effective resistance through the metal. (© APS/Alan Stonebraker).