Mechanical Switching of Nanoscale Multiferroic Phase Boundaries

TL;DR

This paper demonstrates that mechanical stimuli can reversibly switch multiferroic phases and ferroelectric polarization in nanoscale BiFeO3, offering new pathways for energy conversion and sensing technologies.

Contribution

It introduces a novel mechanical switching method for multiferroic phase boundaries at the nanoscale, revealing the microscopic origin of this reversible control.

Findings

Mechanical probe can switch phase boundaries in BiFeO3.

Reversible 180° ferroelectric polarization rotation.

Elastic deformation drives phase reconstruction.

Abstract

Tuning the lattice degree of freedom in nanoscale functional crystals is critical to exploit the emerging functionalities such as piezoelectricity, shape-memory effect, or piezomagnetism, which are attributed to the intrinsic lattice-polar or lattice-spin coupling. Here it is reported that a mechanical probe can be a dynamic tool to switch the ferroic orders at the nanoscale multiferroic phase boundaries in BiFeO 3 with a phase mixture, where the material can be reversibly transformed between the "soft" tetragonal-like and the "hard" rhombohedrallike structures. The microscopic origin of the nonvolatile mechanical switching of the multiferroic phase boundaries, coupled with a reversible 180{\deg} rotation of the in-plane ferroelectric polarization, is the nanoscale pressure-induced elastic deformation and reconstruction of the spontaneous strain gradient across the multiferroic phase boundaries. The reversible control of the room-temperature multiple ferroic orders using a pure mechanical stimulus may bring us a new pathway to achieve the potential energy conversion and sensing applications.