Microscopic origin of electric-field-induced modulation of Curie temperature in cobalt

TL;DR

This paper experimentally demonstrates how electric fields can modulate the exchange coupling and Curie temperature in cobalt films, confirming the microscopic origin of this effect through direct magnetization measurements.

Contribution

It provides the first direct experimental verification of electric-field control of exchange coupling and Curie temperature in a transition metal, aligning with Weiss molecular field theory.

Findings

Electric field influences magnetization reduction with temperature.

Correlation between electric-field-induced Curie temperature modulation and exchange coupling.

Experimental validation of theoretical predictions on electric control of magnetic properties.

Abstract

The Curie temperature is one of the most fundamental physical properties of ferromagnetic materials and can be described by Weiss molecular field theory with the exchange interaction of neighboring atoms. Recently, the electric-field-induced modulation of the Curie temperature has been demonstrated in transition metals. This can be interpreted as indirect evidence for the electrical modulation of exchange coupling. However, the scenario has not yet been experimentally verified. Here, we demonstrate the electrical control of exchange coupling in cobalt film from direct magnetization measurements. We find that the reduction in magnetization with temperature, which is caused by thermal spin wave excitation and scales with Bloch's law, clearly depends on the applied electric field. Furthermore, we confirm that the correlation between the electric-field-induced modulation of the Curie temperature and that of exchange coupling follows Weiss molecular field theory.