Giant converse magnetoelectric effect in a multiferroic heterostructure with polycrystalline Co2FeSi
Shumpei Fujii, Takamasa Usami, Yu Shiratsuchi, Adam Kerrigan, Amran Mahfudh Yatmeidhy, S. Yamada, Takeshi Kanashima, Ryoichi Nakatani, Vlado K. Lazarov, Tamio Oguchi, Yoshihiro Gohda, Kohei Hamaya
Abstract
Abstract To overcome a bottleneck in spintronic applications such as those of ultralow-power magnetoresistive random-access memory devices, the electric-field control of magnetization vectors in ferromagnetic electrodes has shown much promise. Here, we show the giant converse magnetoelectric (CME) effect in a multiferroic heterostructure consisting of the ferromagnetic Heusler alloy Co 2 FeSi and ferroelectric-oxide Pb(Mg 1/3 Nb 2/3 )O 3 -PbTiO 3 (PMN-PT) for electric-field control of magnetization vectors. Using an in-plane uniaxial magnetic anisotropy of polycrystalline Co 2 FeSi film grown on PMN-PT(011), the nonvolatile and repeatable magnetization vector switchings in remanent states are demonstrated. The CME coupling coefficient of the polycrystalline Co 2 FeSi/PMN-PT(011) is over 1.0 × 10 −5 s/m at room temperature, comparable to those of single-crystalline Fe 1- x Ga x /PMN-PT systems. The giant CME effect has been demonstrated by the strain-induced variation in the magnetic anisotropy energy of Co 2 FeSi with an L 2 1 -ordered structure. This approach can lead to a new solution to the reduction in the write power in spintronic memory architectures at room temperature.