利用X光吸收光譜 (X-ray Absorption Spectroscopy, XAS)，研究其以3d過渡金屬摻雜其釔錳氧化物 (YMnO3)-YMn2/3Tm1/3O3 (Tm= Co, Ni and Cu)之電子及原子結構。Mn L3-edge及K-edge結果顯示Tm2+取代了部分Mn3+，而使得Mn離子電荷價數增加。Tm2+的摻雜使得Mn 3d未佔據態變寬而不侷限其局部區域性，進而增進其導電性。由局域密度近似 (Local Spin Density Approximation + Hubbard U parameter，LDA+U)計算電子態密度與X光吸收譜圖比較得知，YMn2/3Ni1/3O3中，造成Mn L3-edge未佔據態改變的是Mn 3d↑-spin eg而不是一般認為的Mn 3d t2g。且O K-edge第二吸收峰為O 2p與Ni 3d↓-spin eg之混成 (hybridized)。 X-ray absorption spectroscopy measurements have been performed to elucidate local electronic and atomic structures of 3d-transition metal doped yttrium manganites (YMnO3) with chemical formula YMn2/3Tm1/3O3 (Tm= Co, Ni and Cu). The Mn L3-edge and K-edge XANES results indicate the direct substitution of Tm2+ for Mn3+, so that the positive effective charge of Mn ions are increased. Tm-doping is also found to induce substantial broadening of the Mn L3-edge feature, which suggests enhancement of the delocalization of Mn 3d eg subbands and conductivity. Local spin density approximation (LDA) + U (Hubbard U parameter) calculation shows that the leading features in the Mn L3-edge XANES spectra of YMn2/3Tm1/3O3 are due to majority-spin Mn eg subband rather than the Mn t2g subband commonly assigned. The comparison between O K-edge XANES spectrum of YMn2/3Ni1/3O3 and the LDA+U calculation shows significant contribution of O 2p and minority-spin Ni 3d eg hybridized states to the second feature of the O K-edge XANES spectra.
