Electric field control of magnetic properties and magneto-transport in composite multiferroics

TL;DR

This paper investigates how electric fields influence magnetic states and electron transport in composite multiferroics, revealing electric control over magnetic phase transitions and magneto-resistance effects near the ferroelectric Curie point.

Contribution

It demonstrates electric field-driven magnetic phase transitions and tunable magneto-resistance in composite multiferroics, highlighting the coupling via Coulomb interaction and the dependence on external electric parameters.

Findings

Magnetic state depends on temperature, electric field, and substrate polarization.

Electric field can induce magnetic phase transitions.

Magneto-resistance exhibits two maxima near ferroelectric transition.

Abstract

We study magnetic state and electron transport properties of composite multiferroic system consisting of a granular ferromagnetic thin film placed above the ferroelectric substrate. Ferroelectricity and magnetism in this case are coupled by the long-range Coulomb interaction. We show that magnetic state and magneto-transport strongly depend on temperature, external electric field, and electric polarization of the substrate. Ferromagnetic order exists at finite temperature range around ferroelectric Curie point. Outside the region the film is in the superparamagnetic state. We demonstrate that magnetic phase transition can be driven by an electric field and magneto-resistance effect has two maxima associated with two magnetic phase transitions appearing in the vicinity of the ferroelectric phase transition. We show that positions of these maxima can be shifted by the external electric field and that the magnitude of the magneto-resistance effect depends on the mutual orientation of external electric field and polarization of the substrate.