Enhanced magnetoresistance in ferromagnetic Pr0.85Ca0.15MnO3/ferroelectric Ba0.6Sr0.4TiO3 superlattice films

Artificial superlattices designed with a ferromagnetic Pr0.85Ca0.15MnO3 insulating layer and ferroelectric Ba0.6Sr0.4TiO3 layer were grown on (100) SrTiO3 substrates. The magnetotransport properties were measured with the current perpendicular to the plane geometry. An increase in magnetoresistance (MR), with no significant low-field effect, was observed as the amount of ferroelectric Ba0.6Sr0.4TiO3 layer thickness increases even up to 9 unit cells. For example, the superlattice [(Pr0.85Ca0.15MnO3)(10)(Ba0.6Sr0.4TiO3)(9)](25) shows a 35% MR at 100 K, though the Pr0.85Ca0.15MnO3 film was a robust insulator with negligible MR even at a high applied magnetic field. Similar superlattice structure, (Pr0.85Ca0.15MnO3)/(SrTiO3) did not show any enhancement in MR. We discussed that the enhanced MR could be due to the ferroelectric spacer layer and the associated magnetoelectric coupling. (C) 2004 American Institute of Physics.