Magnetic measurements on Pr (BrO3)3 ⋅ 9H2O single crystal and a study of the effects and origin of the crystal field

Abstract

Praseodymium bromate was prepared from Pr2O3 and the single crystals of Pr (BrO3)3 ⋅ 9H2O were grown. The principal magnetic susceptibility χ⊥ and the anisotropy χ∥-χ⊥ was measured in the range 300–90 K. The variation of the average magnetic moment peff with temperature is appreciable showing a deviation from the Curie law. The magnetic anistropy χ∥-χ⊥ is found to be much higher than in Pr-ethylsulfate where the Pr3+ ion occupies a site very similar to that in PrBR. A crystal field analysis with a field of D3h symmetry is found to provide an excellent account of the magnetic properties observed by us and Simizu et al. [J. Appl. Phys. 55, 2333 (1984)] from 300 K down to ∼0.06 K. The Hamiltonian was diagonalized in the complete basis of the 3H ground term taking care of the intermediate coupling effects to a large extent. Some important predictions on the electronic heat capacity and the electric quadrupole splitting have been made. An estimate of the crystal field parameters has been made using the available structural data on the crystal and the results are discussed in the light of our phenomenological set of parameters.