Change in the magnetic structure of (Bi,Sm)FeO3 thin films at the morphotropic phase boundary probed by neutron diffraction

TL;DR

This study investigates how Sm doping in BiFeO3 thin films alters their magnetic structure from cycloid to G-type antiferromagnet at the morphotropic phase boundary, linked to enhanced piezoelectric response and potential for multiferroic devices.

Contribution

It provides the first detailed neutron diffraction analysis of magnetic structure evolution in (Bi,Sm)FeO3 thin films across the morphotropic phase boundary.

Findings

Magnetic structure transitions from cycloid to G-type antiferromagnet with increased Sm doping.

Large piezoelectric response observed at the morphotropic phase boundary.

Magnetic structural transition offers potential for room temperature multiferroic applications.

Abstract

We report on the evolution of the magnetic structure of BiFeO3 thin films grown on SrTiO3 substrates as a function of Sm doping. We determined the magnetic structure using neutron diffraction. We found that as Sm increases, the magnetic structure evolves from a cycloid to a G-type antiferromagnet at the morphotropic phase boundary, where there is a large piezoelectric response due to an electric-field induced structural transition. The occurrence of the magnetic structural transition at the morphotropic phase boundary offers another route towards room temperature multiferroic devices.