Electric field effect on magnetism in a MgO/Pd/Co system with a solid-state capacitor structure

Takamasa Hirai,Kentaro Toyoki,Yoshinori Kotani,Tomohiro Koyama,Aya Obinata,Tetsuya Nakamura,Daichi Chiba

doi:10.1063/1.5039680

Abstract

The electric field effect on the magnetism in a MgO/Pd/Co system, in which a magnetic moment is induced in the Pd layer owing to the ferromagnetic proximity effect, has been investigated using various experimental methods. An electric field was applied to the surface of the Pd layer through a solid-state HfO2/MgO dielectric bilayer by applying a gate voltage with a back-gating configuration. Changes in the magnetic properties of the system as a result of gate voltage application were detected using magnetization and polar-Kerr effect measurements as well as X-ray absorption and X-ray magnetic circular dichroism (XMCD) spectroscopies. A systematic change in the magnetic moment of the system by the application of a gate voltage is observed. The magnetic hysteresis loops obtained by the polar-Kerr effect measurement and the element-specific XMCD signal at the Co L3-edge clearly show a reproducible change in the coercivity that is dependent on the gate voltage.

Highlights

INTRODUCTIONDominant.[33,34] To detect changes in the magnetic properties of this system, magnetization and polarKerr effect measurements, and X-ray absorption and X-ray magnetic circular dichroism (XMCD) spectroscopies were used under the application of electric fields
The electric field effect on the magnetism in ferromagnetic materials[1] with a capacitor structure including a magnetic tunnel junction[2,3] has been intensively studied because of its potential to dramatically reduce the power consumption of magnetic memory devices when writing information
An electric field can result in the switching of ferromagnetism itself, i.e., the Curie temperature is tunable by the application of an electric field.[9,10,11,12,13]

Summary

INTRODUCTION

Dominant.[33,34] To detect changes in the magnetic properties of this system, magnetization and polarKerr effect measurements, and X-ray absorption and X-ray magnetic circular dichroism (XMCD) spectroscopies were used under the application of electric fields. The modulated moment for a Pd atom per electron was determined using the linear dependence of the total magnetic moment of the system on the gate electric field. An electric-field modulation of the coercivity was observed in the magnetization curves

SAMPLE STRUCTURE

Capacitance

Electric field effect on the magnetic moment

XMCD measurement

SUMMARY