Figure 5

(a) Temperature-dependent Ni L_3,2-edge X-ray absorption spectra obtained using linearly polarized X-rays with E// c and E⊥ c polarizations, with the corresponding XLD [(E// c) − (E⊥ c)] shown at the bottom. (b) Temperature-dependent variation in the XLD area (integrated over the range of 847–857 eV of the XLD spectra) at the L₃-edge (A_L3), shown to elucidate the thermal evolution of the preferential electron occupancy in the Ni 3d e_g orbital, which switches from in-plane (3d_x²_−y²) to out-of-plane (3d_3z²_−r²) above T_SO (60 K).