Epitaxial Bi9Ti3Fe5O27 thin films: a new type of layer-structure room-temperature multiferroic

Abstract

In this communication, we report the successful growth of high-quality Aurivillius oxide thin films with m = 8 (where m denotes the number of pseudo-perovskite blocks) using pulsed laser deposition. Both the ferroelectric and magnetic properties of the layer-structure epitaxial Bi₉Ti₃Fe₅O₂₇ films were investigated. Surprisingly, the optimized thin films exhibit in-plane ferroelectric polarization switching and ferromagnetism even at room temperature, though the bulk material is antiferromagnetic. In addition, dielectric measurements indicate that such thin films exhibit potential for high-frequency device applications. This work therefore demonstrates a new pathway to developing single-phase multiferroic materials where ferroelectricity and ferromagnetism coexist with great potential for low energy device applications.