100 50 0 -10 -5 0 Intensity (arb. units) 781 780 779 778 777 Photon Energy (eV) 0.7 0.6 0.5 0.4 0.3 0.2 0.1 Magnetization ( GLYPH<s109> B /Co) 100 80 60 40 20 Temperature (K) Zn$_{0.9}$Co$_{0.1}$O Co 2 p$_{3/2}$ XAS XMCD P$_{O2}$ =10 –3  Pa 20 K 40 K  100 K H  = 4.5 T x =0.07,  P$_{O2}$ =10$^{-4}$ Pa, x =0.10,  P$_{O2}$ =10$^{-2}$ Pa, x =0.10,  P$_{O2}$ =10$^{-3}$ Pa, x =0.10,  P$_{O2}$ =10$^{-4}$ Pa (a) (b) Fit function: C ' H /( T – GLYPH<s113> ) +  M$_{s}$ ' H  = 4.5 T  Fitted FIG. 4: (Color online) Temperature dependence of the XMCD spectra of Zn$_{1}$$_{−}$$_{x}$Co$_{x}$O thin films. (a) XMCD spectra of the x = 0 . 10, P$_{O2}$ =10 − 3 Pa sample at H = 4 . 5 T and at various temperatures. (b) T dependence of the total magnetic moment M$_{tot}$ estimated using the XMCD sum rules at H = 4 . 5 T. Solid curves are the results of fitting to the Curie-Weiss law, C $^{′}$H/ ( T − θ ) + M ′ $_{s}$. 19