Piezostrain-controlled magnetization compensation temperature in ferrimagnetic GdFeCo alloy films

The electrical control of magnetization compensation temperature (${T}_{\mathrm{com}}$) is investigated in ferrimagnetic GdFeCo alloy deposited on ferroelectric $\mathrm{Pb}({\mathrm{Mg}}_{1/3}{\mathrm{Nb}}_{2/3}){\mathrm{O}}_{3}\text{\ensuremath{-}}30%\mathrm{PbTi}{\mathrm{O}}_{3}$ (PMN-PT). It is found that the applied electric field can cause a 19 K shift in ${T}_{\mathrm{com}}$. ${T}_{\mathrm{com}}$ under different applied electric fields across the PMN-PT substrate suggests that such electrical control is induced by piezostrain at the ferroelectric-ferrimagnetic interface. Spin-polarized first-principles calculations show that the change of exchange coupling strength in GdFeCo are caused by the lattice strains. Nonvolatile switching of resistance and direct bipolar control of exchange bias are achieved when an electric field is applied to appropriately designed multilayers. Our findings pave the way for electric field control of ${T}_{\mathrm{com}}$ in ferrimagnetic GdFeCo alloy and have implications for the development of energy efficient and nonvolatile ferrimagnetic magnetic random access memory.