Tunneling anisotropic magnetoresistance with half-metallic electrodes

Abstract

Tunneling anisotropic magnetoresistance (TAMR) is the difference in resistance of a magnetic tunnel junction (MTJ) due to a change in direction of the magnetization of one or both of the magnetic electrodes with respect to the flow of current, i.e. tunnel conductance for magnetization in the plane differs from magnetization out of the plane.1-5 This is in contrast to the tunneling magnetoresistance (TMR) effect where resistance can change by hundreds or thousands of percent depending on the relative orientation of the magnetization of the two electrodes.6 Over the past decade, the TMR effect has been used in several data storage applications and is a fundamental element of most spintronics research. Generally, the TAMR effect is much smaller than the TMR effect, being on the order of, at most, a few %, due to the origin of the TAMR effect being spin-orbit coupling (SOC).7,8 Finding a system with large TAMR, however, could expand the functionality of MTJs and open the door to new applications, i.e. multiple (more than two) robust resistance states in a single MTJ.