Antiferromagnet controlled tunneling anisotropic magnetoresistance*

We investigate tunneling anisotropic magnetoresistance (TAMR) in antiferromagnets (AFM)-based junctions, where Co/Pt magnetization drives partial rotation of AFM moments with the formation of exchange-spring [1]. The existence of exchange-spring is further confirmed by element specified x-ray magnetic dichroism [2]. Because of superior thermal tolerance of perpendicular exchange coupling and the stability of moments of $\sim$ 6 nm-thick IrMn in [Pt/Co]/IrMn/AlO$_{\mathrm{x}}$/Pt junctions, TAMR gets significantly enhanced up to room-temperature [1]. The TAMR behavior in [Pt/Co]/IrMn/AlO$_{\mathrm{x}}$/metal junctions is insensitive to the top metal electrodes [3]. The situation turns out to be different when the top electrode is replaced by AFM. TAMR is observed in IrMn/AlOx/IrMn junctions, where the resistance states are governed by the relative arrangement of the AFM moments adjacent to AlO$_{\mathrm{x}}$ [4]. Our findings would advance the process towards practical AFM spintronics. \\[4pt] [1] Y. Y. Wang, et al. Phys. Rev. Lett., 109, 137201 (2012).\\[0pt] [2] Y. Y. Wang, et al. New J. Phys., in press.\\[0pt] [3] Y. Y. Wang, et al. Appl. Phys. Lett., 103, 202403 (2013).\\[0pt] [4] Y. Y. Wang, et al. Adv. Funct. Mater. doi: 10.1002/adfm.201401659.