X-ray magnetic circular dichroism of codeposited C60-Co films with giant tunnel magnetoresistance

Matsumoto, Yoshihiro; Sakai, Seiji; Naramoto, Hiroshi*; Nakagawa, Takeshi*; Takagi, Yasumasa*; Yokoyama, Toshihiko*; Hirao, Norie; Baba, Yuji  ; Shimada, Toshihiro*; Maeda, Yoshihito

Recently, we have found that the codeposited C60-Co films where Co nanoparticles are dispersed into the matrix of the C60-Co compound show large tunnel magnetoresistanene (TMR) effects at low temperatures. The observed MR ratios cannot be explained by a spin-polarization of crystalline Co, so it is expected that the C60-Co compound mediates an enhancing effects to the spin-dependent transport in the films. In the present work, we have investigated the spin states of the C60-Co films by X-ray magnetic circular dichroism spectroscopy. As the results, MCD spectra of the C60-Co compound show the sensitivity to the sample temperature, which is consistent to the temperature dependence of MR ratios. This indicates clearly that spin-polarized states of the C60-Co compound influences the degree of spin-dependent transport in the films.