Piezo Voltage Controlled Planar Hall Effect Devices.

Bao Zhang,Kai-Ming Cai,Kang-Kang Meng,Jian-Hua Zhao,Yu Sheng,Kai-You Wang,Nan Zhang,K W Edmonds,Hou-Zhi Zheng,Hao Zhang,Yang Ji,Mei-Yin Yang

doi:10.1038/srep28458

Abstract

The electrical control of the magnetization switching in ferromagnets is highly desired for future spintronic applications. Here we report on hybrid piezoelectric (PZT)/ferromagnetic (Co2FeAl) devices in which the planar Hall voltage in the ferromagnetic layer is tuned solely by piezo voltages. The change of planar Hall voltage is associated with magnetization switching through 90° in the plane under piezo voltages. Room temperature magnetic NOT and NOR gates are demonstrated based on the piezo voltage controlled Co2FeAl planar Hall effect devices without the external magnetic field. Our demonstration may lead to the realization of both information storage and processing using ferromagnetic materials.

Highlights

Since the spin field effect transistor was proposed by Datta and Das in 1990s, due to the difficulties of spin injection and detection, until now there is still no efficient spin field effect transistor developed1–3
The control of the charge transport in semiconductors by piezo voltages has been demonstrated for high speed piezotronics, which has been proposed for post Complementary Metal Oxide Semiconductor (CMOS) technology29
The Heusler alloy Co2FeAl films used in our planar Hall effect devices were grown by molecular beam epitaxy (MBE)28,30

Summary

Introduction

Since the spin field effect transistor was proposed by Datta and Das in 1990s, due to the difficulties of spin injection and detection, until now there is still no efficient spin field effect transistor developed. Approaches to control the spin of magnet bits electrically, such as spin-orbit torque, magneto-electrical coupling, voltage, polarized light and piezo voltages have been proposed based on ferromagnetic metals. The piezo voltage is one of the most effective methods to control the magnetization switching, in which a deformation of the crystal structure of the magnetic materials induces a change of the magnetocrystalline anisotropy which is directly related with the spin-orbit interaction in the crystal. We demonstrate planar Hall effect devices in which the planar Hall resistances/voltages of ferromagnetic Co2FeAl devices can be tuned by piezo voltages from positive (negative) to negative (positive) effectively, which is associated with magnetization switching in the plane by 90°. Room temperature magnetic NOT and NOR gates are demonstrated based on the Co2FeAl piezo voltage controlled planar Hall effect devices without the external magnetic field. The simple device structure allows us to build large scale building blocks for future logics

Methods

Results

Conclusion