X-ray magnetic circular dichroism and photoemission studies of ferromagnetism in CaMn1-xRuxO3 thin films

We have studied the electronic and magnetic properties of epitaxially grown CaMn(1-x)Ru(x)O(3) thin films (x= 1.0, 0.75, 0.5) by soft x-ray absorption, soft x-ray magnetic circular dichroism (XMCD), and hard x-ray photoemission spectroscopy (HXPES) measurements. The XMCD studies indicated that the spin moments of Mn and Ru are aligned in opposite directions. The valence-band HXPES spectra revealed that the Ru 4d t(2g) states around the Fermi level and the Mn 3d t(2g) up-spin states centered similar to 2 eV below it showed systematic concentration dependences. From these results, we propose that the localized Mn 3d t2g states and the itinerant Ru 4d t(2)g band are antiferromagnetically coupled and give rise to the ferromagnetic ordering, which is in analogy to the mechanism proposed for double perovskite oxides, such as Sr(2)FeMoO(6).