Sir Martin Wood Prize Lecture

8 Jun 2015 - 2:00pm to 3:00pm
Somerville College
Margaret Thatcher Centre
Specialised / research interest

Effective field measurements and spin torque dynamics in magnetic nanostructures

The Sir Martin Wood Prize is awarded annually by the Millenium Science Forum to a young researcher from a Japanese University of Research Institute who has performed outstanding research in the area of condensed matter science. The prize is named after Sir Martin Wood, Founder of Oxford Instruments. We are pleased to report that the 2014 prize winner Dr Masamitsu Hayashi, Senior Researcher at the National Institute of Materials Science, Tsukuba, Japan will be delivering this year's lecture

Strong spin-orbit effects in magnetic heterostructures with broken structural inversion symmetry have opened new paradigms to control magnetic moments electrically[1, 2]. An ultrathin magnetic layer sandwiched between a heavy metal layer and an insulating oxide layer form the base of inversion symmetry broken magnetic heterostructures. In such structures, extremely small current applied along the film plane can trigger magnetization switching and domain wall motion[3, 4]. Key to the power efficient magnetization control is the large spin-orbit coupling of the heterostructure. The strong spin orbit coupling constant of the heavy metal layer enables generation of large spin current that can impinge upon the magnetic layer to exert torque on the magnetic moments, now commonly referred to as the spin-orbit torque. At interfaces, spin orbit coupling can cause the ultrathin magnetic layer to form a chiral magnetic structure, via the Dzyaloshinskii-Moriya interaction, that can be manipulated by the spin current. We have studied the characteristics of spin-orbit torques in ultrathin magnetic heterostructures with magnetization oriented perpendicular to the film plane[5]. The layer thickness and temperature dependence of the torque are analyzed to illustrate the importance of unusual spin transmission at the interface of heavy metal and magnetic layers[6, 7]. Current induced domain nucleation and domain wall motion in related structures will be discussed in connection with the chiral magnetic texture[8] developed in magnetic heterostructures.

For more information contact: 

Olivia Hawkes
Condensed Matter Physics
T: (01865) 272225