Implications of interfacial magnetization for oxide spintronics

Strongly correlated oxides have attracted considerable attention both as a playground for fundamentally new physics and as potential building blocks for advanced devices, because the interplay between their charge, spin, orbital, and lattice degrees of freedom can lead to a wide variety of novel phenomena and functional properties. One example is half metallicity observed in several transition-metal perovskites and double perovskites, which is highly favored for many spintronic applications. However, it is often found that the physical properties are largely altered at oxide interfaces of interest, because the delicate balance among different competing terms can be broken there by several mechanisms, including chemical disorders, strain, broken translational symmetry and charge transfer etc. Interfacial properties, which are in fact crucial for the performance, become extremely difficult to be predicted for oxide spintronics and thus, detailed characterizations of relevant boundary regions are generally required. In this paper, interface-sensitive neutron and x-ray techniques are used to address the structure-property relationships in a ferrimagnetic double-perovskite Sr₂CrReO₆ (SCRO), and magnetic tunneling junctions (MTJs) consisting of ferromagnetic manganite La_0.7Ca_0.3MnO₃ (LCMO) and insulating cuprate PrBa₂Cu₃O₇ (PBCO). This work illustrates that the interface-induced magnetization in layered oxide heterostructures can significantly affect the transport properties thus provides a knob for designing oxide spintronics.