Magnetic susceptibilities, Raman spectroscopy and crystal field analysis of Pr 3+ in monoclinic single crystals of PrPO 4

Single crystals of praseodymium phosphate (PrPO4) are grown by flux method from Pb2P2O7 flux with PbF2 as an additive. The magnetic anisotropy of PrPO4 with different modes of suspensions (b-axis vertical, c-axis vertical and (100) plane horizontal) are measured in the temperature range of 300–80 K. The principal magnetic susceptibilities, χ1 and χ3 are measured from room temperature down to 14 K. The other principal magnetic susceptibility, χ2 is obtained from the value of anisotropy measured with b-axis vertical mode of suspension. The observed magnetic data of PrPO4 has been analyzed using one electron crystal field (CF) theory with rare earth site symmetry as C2v. No ordering effect has been noticed in the observed magnetic data within the temperature range of our study, which indicates that the inter-ionic interaction is of dipolar type. To substantiate the crystal field analysis, the Raman spectra of the single crystal in the wave number range of 0–1800 cm−1 has also been recorded. All the observed data like, magnetic susceptibilities including anisotropies, Stark energies extracted from Raman spectra etc. are considered in the CF analysis. Interestingly, the calculated values of CF electronic Stark energies in all the excited multiplets are in agreement with those extracted from the Raman data. Magnetic data are also successfully fitted by the CF analysis. The CF analysis provides the electronic specific heat capacity which gives Schottky anomalies at ∼48.5 K.