Electric field–induced ferromagnetic domain change by ferroelectric topological domain switching in Co-substituted BiFeO ₃ nanodots

Electric field–induced magnetization reversal accompanying polarization switching is promising for low–power consumption, nonvolatile, voltage-write, magnetic-read memory applications. Perovskite BiFe 0.9 Co 0.1 O 3 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 0.9 Co 0.1 O 3 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.