Magnetism of Ferromagnetic Manganite/Iridate Interfaces

The relationship between spin-orbit coupling (SOC), emergent topological states, and spin Hall effects, which are highly relevant for spintronics, has driven the interest in materials with strong SOC in recent years. Likewise, complex oxide heterostructures have garnished much interest due to emergent interfacial phenomena resulting from the competition between charge, spin, and lattice order parameters, and the ability to tune this competition. The question arises as to whether SOC can result in modified interfacial magnetic states. To explore this possibility we have investigated ferromagnetic La_0.7Sr_0.3MnO₃/SrIrO₃ bilayers deposited on a SrTiO3 substrate. First of all we find that depending on the growth order, the coercive field of the magnetization loop differs significantly at low temperatures. Similar to previous reports, a net moment on Ir has been recorded with element specific XMCD experiments, which is aligned antiparallel to the Mn moments within the manganite. Interestingly, we find that the Ir moment does not follow the same temperature dependence as the magnetization of the manganite, but drops off almost linearly with increasing temperature. Possible origins of this result will be discussed.