Abstract
Understanding the magnetism at the interface between a ferromagnet and an insulator is essential because the commonly posited magnetic "dead" layer close to an interface can be problematic in magnetic tunnel junctions. Previously, degradation of the magnetic interface was attributed to charge discontinuity across the interface. Here, the interfacial magnetism was investigated using three identically prepared La0.67Sr0.33MnO3 (LSMO) thin films grown on different oriented SrTiO3 (STO) substrates by polarized neutron reflectometry. In all cases the magnetization at the LSMO/STO interface is larger than the film bulk. We show that the interfacial magnetization is largest across the LSMO/STO interfaces with (001) and (111) orientations, which have the largest net charge discontinuities across the interfaces. In contrast, the magnetization of LSMO/STO across the (110) interface, the orientation with no net charge discontinuity, is the smallest of the three orientations. We show that a magnetically degraded interface is not intrinsic to LSMO/STO heterostructures. The approach to use different crystallographic orientations provides a means to investigate the influence of charge discontinuity on the interfacial magnetization.
Original language | English |
---|---|
Pages (from-to) | 19307-19312 |
Number of pages | 6 |
Journal | ACS Applied Materials and Interfaces |
Volume | 9 |
Issue number | 22 |
DOIs | |
State | Published - Jun 7 2017 |
Funding
This work was supported by the U.S. Department of Energy (DOE) Office of Science (OS), Basic Energy Sciences (BES), Materials Sciences and Engineering Division (sample design, fabrication, and physical property characterization), and by the Laboratory Directed Research and Development (LDRD) Program of Oak Ridge National Laboratory, managed by UT-Battelle, LLC, for the U.S. DOE (PNR). The research at ORNL's Spallation Neutron Source was sponsored by the Scientific User Facilities Division, BES, U.S. DOE.
Keywords
- charge discontinuity
- interfacial magnetization
- magnetic "dead" layer
- polarized neutron reflectometry