Effects of ferroelectric-poling-induced strain on magnetic and transport properties of La0.67Ba0.33MnO3 thin films grown on (111)-oriented ferroelectric substrates

摘要

La0.67Ba0.33MnO3 thin films were epitaxially grown on (111)-oriented 0.31Pb(In1/2Nb 1/2)O3-0.35Pb(Mg1/3Nb2/3)O 3-0.34PbTiO3 ferroelectric single-crystal substrates. During ferroelectric poling and polarization rotation, the resistance of La 0.67Ba0.33MnO3 films tracks the electric-field-induced in-plane strain of substrates effectively, implying strain-mediated coupling. Upon poling along the [111] direction, ferromagnetism is suppressed for T < 175 K, but enhanced for T > 175 K, which is explained by magnetoelastic coupling that modifies the film's magnetic anisotropy. Our findings also show that the magnetic field has an opposite effect on the strain-tunability of resistance [i.e., (ΔR/R)strain] above and below the Curie temperature TC, which is interpreted within the framework of phase separation.