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

Terai, Kota*; Yoshii, Kenji  ; Takeda, Yukiharu   ; Fujimori, Shinichi   ; Saito, Yuji  ; Owada, Kenji; Inami, Toshiya; Okane, Tetsuo  ; Arita, Masashi*; Shimada, Kenya*; Namatame, Hirofumi*; Taniguchi, Masaki*; Kobayashi, Keisuke*; Kobayashi, Masaki*; Fujimori, Atsushi*

We have studied the electronic and magnetic properties of epitaxially grown CaMnRuO thin films ( = 1.0, 0.75, 0.5) by soft X-ray absorption (XAS), 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 4 states around the Fermi level and the Mn 3 up-spin states centered 2 eV below it, both of which showed systematic concentration dependences. From these results, we propose that the localized Mn 3 states and the itinerant Ru 4 band are antiferromagnetically coupled and give rise to the ferromagnetic ordering, in analogy to the mechanism proposed for double perovskite oxides such as SrFeMoO.