Electrical and thermal control of magnetic coercive field in ferromagnetic/ferroelectric heterostructures

Abstract

We report the growth of ferromagnetic epitaxial CoFe${}_{2}$O${}_{4}$ (CFO) thin films on 011-oriented tetragonal-structured 0.62Pb(Mg,Nb)O${}_{3}$-0.38PbTiO${}_{3}$ single crystal substrates. In the substrates, electric field-induced polarization reorientation resulted in maximum strains of \ensuremath{-}1.3% and 0.64% along in-plane 100 and along in-plane $0\overline{1}1$, respectively. As a consequence, in the CFO films, irreversible magnetic coercive field changes of 580, \ensuremath{-}510, and \ensuremath{-}220 Oe were observed along in-plane 100 and $0\overline{1}1$ and out-of-plane 011, respectively, after electric field poling. After annealing at 470 K, the substrate depoled, and both the magnetic coercive fields and the remnant magnetizations along the three directions recovered their original values.