Tunneling anisotropic magnetoresistance in MgO-based magnetic tunnel junctions induced by spin-orbit coupling

We performed a first-principles study of the tunneling anisotropic magnetoresistance (TAMR) in Ag(Ir,Pt)/MgO/Fe junctions. An enhanced TAMR of the order of 10% is found in the junctions at the equilibrium state, which shows ideal and skewed fourfold angular dependence for the in-plane and out-of-plane TAMR, respectively. The TAMR effect in the junctions shows a simple barrier thickness dependence with the largest TAMR effect present in the junction with an $\ensuremath{\sim}6$-monolayer MgO barrier. The interfacial states due to the spin-orbit coupling effect should be responsible for the complex and enhanced TAMR effect found in these junctions. A little interfacial oxygen vacancy disorder at the Fe/MgO interface can noticeably deteriorate the TAMR effect.