Low-temperature magnetic susceptibilities and anisotropy of Pr 3+ diglycollate crystal

Abstract

The results of measurement of magnetic susceptibilities and anisotropies of single crystals of Pr 3+ diglycollate (PrDG), between 300 and 21 K are reported. A change in the sign of the magnetic anisotropy K ‖ ≈ K ⊥ was observed at T = 42 K. In other Pr 3+ compounds, similar change of sign has also been observed at different temperatures. Such inversion characteristics have been explained by the crystal field (CF) effect. The magnetic behaviour of PrDG did not suggest phase change effect in the temperature range of this study. Magnetic and optical experimental data were analysed considering a very general form of the CF Hamiltonian, allowing for J mixing of 91 ‖SLJM J 〉 states of the 4f 2 configuration of Pr 3+, suitably modified under an intermediate coupling formalism, compatible with Pr 3+ in the diglycollate host. The best fitting parameters were found to be E 1 = 4730.0, E 2 = 22.16, E 3 = 467.5, ζ = 734.0, α = 25.9, β = −694.0, γ = 1520.0, B 20 = 145.0, B 40 = − 1300.0, B 60 = 650.0, B 66 = 600.0, B 43 = 1300.0, B 63 = − 300.0 (all in cm −1). The CF levels of the ground term 3H 4 were determined accurately, which permitted the calculation of the Schottky specific heat ( C sh) down to 2 K.