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 similar to 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.

Automated summary

We conducted a first-principles study on the tunneling anisotropic magnetoresistance (TAMR) in Ag(Ir,Pt)/MgO/Fe junctions. An enhanced TAMR effect of approximately 10% was found in these junctions at the equilibrium state, exhibiting ideal and skewed fourfold angular dependence for in-plane and out-of-plane TAMR, respectively. The TAMR effect showed a simple barrier thickness dependence, with the largest effect observed in the junction with a 6-monolayer MgO barrier. The complex and enhanced TAMR effect in these junctions is believed to be attributed to interfacial states induced by spin-orbit coupling, while even a slight interfacial oxygen vacancy disorder at the Fe/MgO interface can noticeably deteriorate the TAMR effect.