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Voltage Control of Spin Waves in Nanostructures

by Yu-Jin Chen

Institution:	University of California Irvine
Year:	2017
Keywords:	Condensed matter physics; micromagnetics; nanostructures; parametric resonance; spintronics; spin waves; voltage-controlled magnetic anisotropy
Posted:	02/01/2018
Record ID:	2170861
Full text PDF:	http://www.escholarship.org/uc/item/4fh5f6f7

Abstract

This dissertation describes the experiments that investigate new methods to control spin waves by electric field. In one experiment, we excite parametric resonance of magnetization in nanoscale magnetic tunnel junctions, which are multilayer thin film devices patterned into nanopillar shape. One of the layers possesses strong perpendicular magnetic anisotropy and exhibits strong voltage-controlled magnetic anisotropy. This magneto-electric effect allows one to modulate the perpendicular magnetic anisotropy of the layer and parametrically excite large-amplitude oscillations of the magnetization. The results of this experiment show that it is possible to parametrically excite resonance in a magnetic nanostructure using electric field and that the threshold voltage for this process is low: it is found to be well below 1 Volt. In addition, we developed nanodevices which allow us to test the effects of voltage-controlled magnetic anisotropy on spin wave propagation. It is hoped that this work will pave the way towards developing energy-efficient spintronic devices based on manipulation of spin waves using electric field.