Voltage-Controlled Surface Magnetization of Itinerant Ferromagnet Ni_(1-x)Cu_x

TL;DR

This paper proposes a method to electrically control surface magnetization in Ni-Cu alloys by tuning electron density near the ferromagnetic boundary, enabling isothermal switching of magnetization.

Contribution

It introduces a theoretical framework combining Ginzburg-Landau functional and ab-initio data to predict voltage-controlled surface magnetization in Ni-Cu alloys.

Findings

The effect is theoretically shown to be experimentally observable.

Surface magnetization can be switched on and off by voltage.

The approach applies to materials near the para- and ferromagnetic boundary.

Abstract

We argue that surface magnetization of a metallic ferromagnet can be turned on and off isothermally by an applied voltage. For this, the material's electron subsystem must be close enough to the boundary between para- and ferromagnetic regions on the electron density scale. For the 3d series, the boundary is between Ni and Cu, which makes their alloy a primary candidate. Using Ginzburg-Landau functional, which we build from Ni_(1-x)Cu_x empirical properties, ab-initio parameters of Ni and Cu, and orbital-free LSDA, we show that the proposed effect is experimentally observable.