Strain-mediated electric-field control of photoinduced demagnetization in La0.8Ca0.2MnO3 thin films

La0.8Ca0.2MnO3 (LCMO) thin films have been epitaxially grown on ferroelectric 0.67Pb(Mg1/3Nb2/3)O-3-0.33PbTiO(3) (PMN-PT) substrates. The substrate-induced strain effects on the transport and photoinduced demagnetization in LCMO films were investigated. The photoinduced resistances (PRs) of LCMO systematically changed versus temperature before and after ferroelectric-poling on PMN-PT, indicating that photoexcited extra carriers in LCMO may suppress the neighboring spin correlation due to the photoassisted hopping of anti-Jahn-Teller polarons. Moreover, a significant modulation on PR by electric fields applied across PMN-PT was observed. In situ x-ray diffraction indicates that the observed variations result from substrate-induced strain due to the ferroelectric polarization or converse piezoelectric effect. (C) 2011 American Institute of Physics. [doi:10.1063/1.3556613]