Voltage control of magnetization easy-axes: a potential candidate for spin switching in future ultrahigh-density nonvolatile magnetic random access memory

We report a challenging attempt to switch magnetization directions in ferromagnetic films by applying a voltage instead of an external magnetic field. As an example, a voltage control of magnetization easy-axes in a newly developed hybrid system of ferromagnetic/piezoelectric films has been demonstrated by using the well-known effects of both the inverse magnetostriction of ferromagnetic CoPd alloys and the inverse piezoelectricity of lead-zirconate-titanate alloy films. This information-storage and writing method suitable for use in an ultrahigh-density nonvolatile magnetic random access memory may prove to be a new paradigm in information-storage technology.