Giant magnetoelectric effect in an L21-ordered Co2FeSi/Pb(Mg1/3Nb2/3)O3-PbTiO3 multiferroic heterostructure

We experimentally show a giant magnetoelectric (ME) effect at room temperature in an interfacial multiferroic heterostructure consisting of L21-ordered Co2FeSi and Pb(Mg1/3Nb2/3)O3-PbTiO3 (PMN-PT). Molecular beam epitaxy growth at 400 °C enables us to obtain epitaxial and L21-ordered Co2FeSi films on PMN-PT(001). For the epitaxial Co2FeSi/PMN-PT heterostructure, the remanent magnetization state can be largely modulated by varying electric fields. We note that the room-temperature ME coupling coefficient (α) is estimated to be 6.0–6.3 ×10−6 s/m, comparable to the highest α value reported previously. Nonvolatile and repeatable magnetization changes in remanent states are also demonstrated. These results will pave the way for room-temperature electric-field control of the magnetization of half-metallic Heusler alloys in high-performance spintronic devices.