Electric field-induced ferromagnetic domain change by ferroelectric topological domain switching in Co-substituted...

Electric field-induced magnetization reversal accompanying polarization switching is promising for low-power consumption, nonvolatile, voltage-write, magnetic-read memory applications. Perovskite BiFe_0.9Co_0.1O₃ is a room-temperature multiferroic material in which both ferroelectric and weakly ferromagnetic orders coexist, with spontaneous magnetization coupled to the ferroelectric polarization. Here, we report electric field-induced ferroelectric and ferromagnetic domain changes in BiFe_0.9Co_0.1O₃ nanodots using a combination of piezoresponse microscopy and scanning nitrogen-vacancy center magnetometry assisted by image analysis techniques to directly observe both ferroic orders on the nanometer scale. The complex ferroelectric domains present in a 190-nanometer structure which can be switched from a net-down to a net-up polarization by scanning with a biased cantilever, accompanied by reversal of both in-plane and out-of-plane components of the magnetization. This directly demonstrates electric field-induced magnetization reversal accompanying 180° polarization switching in a complex structure of a scale relevant to the semiconductor industry, creating a potential path for next generation memory devices.