Control of the strain and magnetoresistance of LaMnO[sub 3+δ] thin films using the magnetostriction of Terfenol-D alloy

Abstract

We have fabricated a magnetoelectric laminate structure composed of magnetostrictive Tb[sub 0.3]Dy[sub 0.7]Fe[sub 1.92] (Terfenol-D) alloy and LaMnO[sub 3+δ] (LMO)/0.67Pb(Mg[sub ⅓]Nb[sub ⅔])O₃–0.33PbTiO₃ (PMN–PT) structure where the LMO film is epitaxially grown on the piezoelectric PMN–PT single-crystal substrate. When an external dc magnetic field is applied perpendicular to the film plane, the magnetoresistance of the LMO film at 220 K under a magnetic field of 1.2 T for the LMO/PMN–PT/Terfenol-D structure is enhanced by 31.6% with respect to that for the LMO/PMN–PT structure without Terfenol-D. Measurements of the magnetoelectric effects of the LMO/PMN–PT/Terfenol-D structure indicate that the strain induced by the magnetostriction of the Terfenol-D alloy is transferred to the PMN–PT substrate, which induces changes in the strain state of the PMN–PT substrate, thereby modifying the strain and magnetoresistance of the epitaxial LMO film.