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Voltage-Controllable Magnetoelectrics: New Thin Film Material and Characterization
The active research effort to find a suitable replacement for complementary metal-oxide-semiconductor devices is of focus in many industrial and academic institutions. Many candidates have been proposed to achieve non-volatile ultra-low power memory and logical devices with high switching speed. A particular promising path towards this type of devices is based on voltage-controlled magnetoelectric effect in antiferromagnetic insulators. In order to advance the understanding of magnetoelectric antiferromagnets, especially the one associated with voltage-controlled antiferromagnetic order parameter switching, we conducted experimental investigation from two distinguished perspectives, both of which have implications for the realization of the fore-mentioned spintronic devices. Specifically, progress is achieved through the implementation of novel experimental methodologies and fabrication techniques of magnetoelectric thin films of an antiferromagnetic material, which hitherto has not been investigated in thin film geometry. Most noticeably, a table-top magneto-optical setup, which allows simultaneous measurements of electric field induced Faraday and Kerr effects, was realized. The historically challenging problem of monitoring the reversal of the antiferromagnetic order parameter is solved for the particular class of magnetoelectric antiferromagnets with our new magneto-optical setup. Meanwhile, the frequency dependence of the electric field induced Faraday effect is experimentally investigated, confirming the prediction of a crystal-field theory. Additionally, employing pulsed laser deposition, highly (110) textured films of magnetoelectric Fe2TeO6 were fabricated for the first time. Structural and magnetic characterization is thoroughly conducted, providing evidence for both the magnetoelectricity of the films and the universality of the boundary magnetization.
Wang, Junlei, "Voltage-Controllable Magnetoelectrics: New Thin Film Material and Characterization" (2017). ETD collection for University of Nebraska - Lincoln. AAI10606180.