X-ray Absorption Spectroscopy Study of Thickness Effects on the Structural and Magnetic Properties of Pr2-δNi1-xMn1+xO6-y Double Perovskite Thin Films

In this work, we report a systematic study of the influence of film thickness on the structural and magnetic properties of epitaxial thin films of Pr2-delta Ni1-xMn1+xO6-y (PNMO) double perovskite grown on top of two different (001)-SrTiO3 and (001)-LaAlO3 substrates by RF magnetron sputtering. A strong dependence of the structural and magnetic properties on the film thickness is found. The ferromagnetic transition temperature (T-C) and saturation magnetization (Ms) are found to decrease when reducing the film thickness. In our case, the thinnest films show a loss of ferromagnetism at the film-substrate interface. In addition, the electronic structure of some characteristic PNMO samples is deeply analyzed using X-ray absorption spectroscopy (XAS) and X-ray magnetic circular dichroism (XMCD) measurements and compared with theoretical simulations. Our results show that the oxidation states of Ni and Mn ions are stabilized as Ni2+ and Mn4+, thus the ferromagnetism is mainly due to Ni2+-O-Mn4+ superexchange interactions, even in samples with poor ferromagnetic properties. XMCD results also make evident large variations on the spin and orbital contributions to the magnetic moment as the film's thickness decreases.

Automated summary

This study systematically investigates the influence of film thickness on the structural and magnetic properties of PNMO double perovskite thin films. The results show a strong correlation between the film thickness and the structural and magnetic properties. The thinnest films exhibit a loss of ferromagnetism. Furthermore, through XAS and XMCD measurements and theoretical simulations, significant variations in the spin and orbital contributions to the magnetic moment are observed as the film thickness decreases.