Magnetic anisotropy control by applying an electric field to the side surface of ferromagnetic films

Hiroshi Terada,Le Duc Anh,Yoshihiro Iwasa,Shinobu Ohya,Masaaki Tanaka

doi:10.1038/s41598-017-05799-8

Abstract

Reducing the power consumption necessary for magnetization reversal is one of the most crucial issues facing spintronics devices. Electric field control of the magnetic anisotropy of ferromagnetic thin films is a promising method to solve this problem. However, the electric field is believed to be effective only within several nanometres of the surface in ferromagnetic metals because of its short Thomas-Fermi screening length, which prevents its practical application to devices. Herein, we successfully modulate the magnetic anisotropy of the entire region of the ferromagnetic layers in the elongated mesas of vertical spin field-effect transistors with widths as large as ~500 nm by applying an electric field to the side surface of the metallic GaMnAs-based mesas through an electric double layer. Our results will open up a new pathway for spintronics devices with ultra-low power consumption.

Highlights

The electric field control of ferromagnetism is expected to be a key technique for future low-energy, non-volatile spintronics devices1–4
We successfully achieved a modulation ratio of the drain-source current IDS up to ~20%, which is much larger than that obtained in the previous study on a vertical spin MOSFET (~0.5%)13, and we obtained a large MR ratio (~5%) that was 50–1000 times as large as those observed in studies of conventional planar spin field-effect transistors8–10
We found that the magnetic anisotropy of the ferromagnetic layers is modulated by the electric field (Fig. 1b,f)

Summary

Introduction

The electric field control of ferromagnetism is expected to be a key technique for future low-energy, non-volatile spintronics devices1–4. The Curie temperature and magnetic anisotropy of ferromagnetic thin films have been shown to be modulated by a gate electric field applied to the top surface of the films.

Results

Conclusion