摘要
We studied the Co valences and spin states in electron-doped LaCo 1-y Te y O 3 by measuring X-ray absorption spectra and electron spin resonance. The low-temperature insulating state involves the low-spin Co 3+ state (S = 0) and the high-spin Co 2+ state, where the latter is described by g = 3.8 and j eff = 1/2. The results, in concurrence with the electron-hole asymmetry confirmed in the electrical resistivity, coincide with the spin-blockade phenomenon in this system. Furthermore, we discuss the g factor in terms of the strong covalent-bonding nature and consider multiple origins of this phenomenon.