Magnetic and soft X-ray absorption spectroscopy characterization of Mn and Co doped lithium nickel phosphate LiNiPO 4

Measurements of magnetic susceptibility as a function of temperature and soft metal and oxygen K X-ray absorption spectra were applied for the characterization of Mn and Co doped LiNiPO. It was established on the basis of measurements of magnetic susceptibility as a function of temperature that the replacement of 10% of Ni by Mn in LiNiPO increases the antiferromagnetic phase transition temperature from 21.3 to 22.8 K, while the same amount of cobalt decreases the Néel temperature to 21.0 K. The experimental Ni, Mn, and Co X-ray absorption spectra compared with the results of crystal field atomic multiplet calculations showed that Ni, Mn, and Co ions are in the 2 + valence states. According to our O K X-ray absorption spectra, there are no doping states in the band gap of Mn and Co doped lithium nickel phosphate.