DEPENDENCIA DE LA TC CON ESPESOR RELATIVO EN BICAPAS FERROANTIFERRO DEL SISTEMA La1-XCaXMnO3

Abstract

Bilayers of the La1-XCaXMnO3 system manganite type in their Ferromagnetic La2/3Ca1/3MnO3 (F-LCMO) and antiferromagnetic La1/3Ca2/3MnO3 (AF-LCMO) phase were grown on (100) oriented SrTiO3 monocrystalline substrates. The bilayers were grown in situ by using a dc sputtering technique at high oxygen pressure and at a substrate temperature of 850 °C and pressure of 3,5 mbar. On the substrate we grew the antiferromagnetic-layer with a given Antiferromagnetic thickness, tAF and then the ferromagnetic layer on the AF-layer, with a given F thickness, tF. The ratio of tAF/tF thickness varied maintaining constant the total thickness of the bilayer in 70 nm. The temperature dependence of the magnetization curves for different applied magnetic field cooling, HFC, (100 Oe – 1000 Oe) show that saturation magnetization, M(0), increases with the increasing of HFC. We determined the transition temperature, Tc, for each thermal demagnetization curve, M(T). The transition temperature, Tc, shows an increase with the increasing of the applied field and a shift toward bigger values with the increase of the ferromagnetic layer in the bilayer.