Structure, magnetic and transport properties of Li-doped

Structure, spectrum, magnetic, and transport properties of the compounds Cu1−xLixCr2Se4 ( x = 0 – 0.7 ) have been experimentally investigated. X-ray photoelectron spectroscopy spectra (XPS) suggest dominant monovalent Cu+ in the samples. With Li+ substitution for Cu+, the ground state changes from ferromagnetic metal to ferromagnetic insulator due to the suppression of the holes in a ligand Se p –Cu d orbitals, leading to the decrease of the saturation moment M s . Both the spectrum and the magnetic results suggest that Lotgering’s model of Cu+[Cr3+]2Se4 is relevant. There is an inner compressive strain in the system, which results in thermal hysteresis in M ( T ) and ρ ( T ) curves.