LSCO: Consistent agreement for electronic structure and experimental X-ray spectra

We have investigated magnetic properties of La$_{\mathrm{1-x}}$Sr$_{\mathrm{x}}$CoO$_{\mathrm{3}}$ (LSCO) as a function of Sr doping with X-ray absorption spectroscopy (XAS), x-ray magnetic circular dichroism(XMCD) at the O K edge and a first principles method. Experiment shows the peak of the oxygen XAS at beginning of the edge is increased with increasing Sr doping. The calculations, using supercells, are in good agreement with detailed XAS of the O K-edge as a function of doping. XMCD calculations reproduce the full experimental spectrum well, and show an increase of the magnetic moment on the oxygen with the number of Sr nearest neighbors. The calculations show that the hybridization involving Co d- and O-p electrons is the key factor for obtaining agreement with the changing XAS spectra as a function of doping. In this talk, we will discuss the XAS, XMCD results and the large external magnetic field effects on the ground state of LSCO(x$=$0).