Magnetoelectric Effects on Composite Nano Granular $Fe/TiO_{2-\delta}$ Films

TL;DR

This study reports the measurement of magnetoelectric effects in nano granular Fe/TiO₂−δ composite films at temperatures below 50 K using a novel experimental technique, revealing significant low-temperature magnetoelectric resistance.

Contribution

The paper introduces a new measurement method for magnetoelectric response in composite films and demonstrates magnetoelectric effects at low temperatures in Fe/TiO₂−δ films, which are unique compared to high-temperature behaviors.

Findings

Magnetoelectric resistance is significantly larger below 50 K.

The resistance exhibits even symmetry with respect to magnetic field reversal.

The composite films show magnetoelectric effects at low temperatures and anomalous Hall effects at high temperatures.

Abstract

Employing a new experimental technique to measure magnetoelectric response functions, we have measured the magnetoelectric effect in composite films of nano granular metallic iron in anatase titanium dioxide at temperatures below 50 K. A magnetoelectric resistance is defined as the ratio of a transverse voltage to bias current as a function of the magnetic field. In contrast to the anomalous Hall resistance measured above 50 K, the magnetoelectic resistance below 50 K is significantly larger and exhibits an even symmetry with respect to magnetic field reversal $H\to -H$. The measurement technique required attached electrodes in the plane of the film composite in order to measure voltage as a function of bias current and external magnetic field. To our knowledge, the composite films are unique in terms of showing magnetoelectric effects at low temperatures, $<$ 50 K, and anomalous Hall effects at high temperatures, $>$ 50 K.