Coaction and competition between the ferroelectric field effect and the strain effect in Pr _0.5Ca _0.5MnO ₃ film/0.67Pb(Mg _1/3Nb _2/3)O ₃-0.33PbTiO ₃ crystal heterostructures

The coaction and competition between the ferroelectric field effect and the strain effect in Pr _0.5Ca _0.5MnO ₃ (PCMO) film/0.67Pb(Mg _1/3Nb _2/3)O ₃-0.33PbTiO ₃ crystal heterostructures were studied. Based on different types of resistance-electric field hysteresis loops at various temperatures, it is clearly identified that the strain effect dominates over the ferroelectric field effect for temperature T above the charge-ordering temperature T _CO of PCMO. With the strong localization of charge carriers for T T _CO, the ferroelectric field effect strongly competes with the strain effect and finally dominates over the latter for T 0.8T _CO. Moreover, the poling-induced strain effect is considerably enhanced by a magnetic field, demonstrating the important role of the phase separation in understanding the strain effect in such heterostructures.