Realization of full magnetoelectric control at room temperature

Kee Hoon Kim

The control of magnetization by an electric field at room temperature remains as one of the great challenges in materials science. Multiferroics, in which magnetism and ferroelectricity coexist and couple to each other, could be the most plausible candidate to realize this long-sought capability. While recent intensive research on the multiferroics has made significant progress in sensitive, magnetic control of electric polarization, the electrical control of magnetization, the converse effect, has been observed only in a limited range far below room temperature. Here we demonstrate at room temperature the control of both electric polarization by a magnetic field and magnetization by an electric field in a multiferroic hexaferrite Ba0.52Sr2.48Co2Fe24O41. The electric polarization in this compound rapidly increases in low magnetic fields (~5 millitesla), and its magnetoelectric susceptibility reaches the highest value (3200 picosecond per meter) among single-phase materials. The magnetization is then modulated up to 0.62 B per formula unit in an electric field of 1.14 MV/m. Furthermore, this compound allows nonvolatile, magnetoelectric read-and-write operations entirely at room temperature. Four different magnetic/electric field writing conditions generate repeatable, distinct magnetization versus electric field curves without dissipation, offering an unprecedented opportunity for multi-bit memory- or spintronic device-applications.