Magnetic properties in perovskite titanates ATiO3-δ (A = Ca, Sr, Ba) were investigated before and after arc melting. Crystal structure analysis was conducted by powder synchrotron X-ray diffraction with Rietveld refinements. Quantitative chemical element analysis was carried out by X-ray photoelectron spectroscopy. Magnetic measurements were conducted by vibrating sample magnetometer and X-ray magnetic circular dichroism (XMCD). The magnetic properties are found to be affected by impurities of 3d elements such as Fe, Co, and Ni. Depending on the composition and crystal structure, the occupation of the magnetic ions in perovskite titanates is selectively varied, which is interpreted to be the origin of the different magnetic behaviors in arc-melted perovskite titanates ATiO3-δ (A = Ca, Sr, Ba). In addition, both formation of oxygen vacancies and the reduction of Ti4+ to Ti3+ during arc-melting also play a role as proven by XMCD. Nevertheless, preferential site occupation of magnetic impurities is dominant in the magnetic properties of arc-melted perovskite ATiO3-δ (A = Ca, Sr, Ba).

The authors are grateful to European Synchrotron Radiation Facility (ESRF), the synchrotron light source KARA and the Karlsruhe Nano Micro Facility (KNMF) for the provision of beamtimes. The authors are indebted to Mr. Samir Hammoud at the Max Planck Institute for Intelligent Systems for the chemical analysis (ICP-OES, hot gas extraction). Open Access funding enabled and organized by Project DEAL.