AVS 62nd International Symposium & Exhibition
    Magnetic Interfaces and Nanostructures Tuesday Sessions
       Session MI+SA-TuA

Paper MI+SA-TuA10
A Depth-Dependent Model for Atomic Valence in Magnetoelectric Systems

Tuesday, October 20, 2015, 5:20 pm, Room 230A

Session: Spin Currents, Spin Textures and Hybrid Magnetic Structures
Presenter: Mikel Holcomb, West Virginia University
Authors: M. Holcomb, West Virginia University
R. Trappen, West Virginia University
J. Zhou, West Virginia University
Y-H. Chu, National Chiao Tung University
S. Dong, Southeast University
Correspondent: Click to Email
Interfacial magnetoelectricity across a multilayer system is known to sometimes result in much larger coupling between electric and magnetism than in single phase systems. The cause has been controversial, but the atomic valence of the magnetic element in these systems is known to change with an applied voltage. We wanted to understand how the interfacial atomic valence was effected as a function of film thickness in thin films of La0.7Sr0.3MnO3 on PbZr0.2Ti0.8O3. To separate the Mn valence at the interfacial layer with PZT from the bulk region of LSMO, we took advantage of the drastically different attenuation length of two techniques: x-ray absorption in L-edge total electron yield mode and K-edge fluorescence yield mode. By globally fitting both sets of experimental results, we were able to develop a depth-dependent model to estimate the layer by layer valences in our materials as a function of thickness. This empirical model was developed under the guidance of theoretical work from a two-orbital double exchange model, which also explored the effects of substrate termination and ferroelectric polarization direction. Estimates based on the data and models for surface, interface and bulk valence as well as surface and interface length scales will be discussed.