Enhanced magnetic and ferroelectric properties in Pb(Zr0.52Ti0.48)O3/La0.7Ca0.3MnO3 bilayers grown on Nb-doped (110) SrTiO3 substrate

Abstract

Epitaxial Pb(Zr0.52Ti0.48)O3/La0.7Ca0.3MnO3 (PZT/LCMO) bilayers with different LCMO thicknesses were deposited on Nb-doped (110) SrTiO3 substrates by pulsed laser deposition. The effects of the LCMO thickness on the ferroelectric and magnetic properties of the PZT/LCMO bilayers were studied. X-ray diffraction and TEM results showed that the lower LCMO layer has grown epitaxially on the NSTO substrate, and the upper PZT layer has grown epitaxially on the lower LCMO layer. The magnetic and ferroelectric properties of the PZT/LCMO bilayers increased with increasing the LCMO thickness, due to the change of the strain state in the LCMO and PZT layers. The in-plane tensile strain in the LCMO layer was relaxed with increasing the LCMO thickness, so that in which the Curie temperature and saturation magnetization were enhanced; the tensile strain in the out-of-plane direction in the PZT layer increased with increasing the LCMO thickness, which causes the increase of ferroelectric properties. Our results demonstrate that for the PZT/LCMO bilayers, the thickness of LCMO layer not only affects its own magnetic properties, but also the ferroelectric properties of the upper PZT layer, indicating that by optimizing the thickness of each layer will improve the multiferroic performance of the bilayers.