Effect of the thickness of BiFeO{sub 3} layers on the magnetic and electric properties of BiFeO{sub 3}/La{sub 0.7}Sr{sub 0.3}MnO{sub 3} heterostructures

BiFeO{sub 3} layers with various thicknesses were fabricated on La{sub 0.7}Sr{sub 0.3}MnO{sub 3} covered SrTiO{sub 3} substrates by a laser molecular-beam epitaxy system. The ferromagnetic transition temperature (T{sub c}) and magnetic coercive field (H{sub c}) of BiFeO{sub 3}/La{sub 0.7}Sr{sub 0.3}MnO{sub 3} heterostructures are larger than those of the La{sub 0.7}Sr{sub 0.3}MnO{sub 3} film. With increasing the thickness of the BiFeO{sub 3} layer, T{sub c}, H{sub c}, and ferroelectric coercive field of the BiFeO{sub 3}/La{sub 0.7}Sr{sub 0.3}MnO{sub 3} heterostructures decrease, while the dielectric permittivity, remanent polarization, and resistance ratio of the ON and OFF states increase. The variations of the magnetic and electric properties with the thickness could be due to the effects of the epitaxial strain and the interface layer.