Nonvolatile, reversible electric-field controlled switching of remanent magnetization in multifunctional ferromagnetic/ferroelectric hybrids

In spin-mechanics, the magnetoelastic coupling in ferromagnetic/ferroelectric hybrid devices is exploited in order to realize an electric-voltage control of magnetization orientation. To this end, different voltage-induced elastic strain states are used to generate different magnetization orientations. In our approach, we take advantage of the hysteretic expansion and contraction of a commercial piezoelectric actuator as a function of electrical voltage to deterministically select one of two electro-remanent elastic strain states. We investigate the resulting magnetic response in a nickel thin film/piezoelectric actuator hybrid device at room temperature, using simultaneous magneto-optical Kerr effect and magnetotransport measurements. The magnetic properties of the hybrid can be consistently described in a macrospin model, i.e., in terms of a single magnetic domain. At zero external magnetic field, the magnetization orientation in the two electro-remanent strain states differs by 15 degrees, which corresponds to a magnetoresistance change of 0.5%. These results demonstrate that the spin-mechanics scheme indeed enables a nonvolatile electrically read-and writable memory bit where the information is encoded in a magnetic property. (C) 2011 American Institute of Physics. [doi:10.1063/1.3624663]