Magnetic properties of Ce³⁺ in PbCeA (A= Te, Se, S)

¹ American University of Beirut, Department of Physics, Bliss Street, PO Box 11-0236 Beirut, Lebanon
² Instituto de Física, Universidade de São Paulo, 05315-970, São Paulo, Brazil
³ Laboratoire Charles Coulomb UMR 5221, Université Montpellier 2, Place Eugène Bataillon - CC069, F-34095 Montpellier Cedex 5 - France
⁴ Institute of Physics, Polish Academy of Sciences, Pl.02-668 Warsaw, Poland

Abstract

The magnetic susceptibility of Pb_1-xCe_xA (A = S, Se and Te) crystals with 0.006 ≤  x ≤ 0.036  were studied in the temperature range from 20 mK up to room temperature. X-band (~9.5 GHz) Electron Paramagnetic Resonance (EPR) showed small shifts in the effective Landé factors that were attributed to crystal-field admixture. The EPR measurements were correlated with the magnetic susceptibility data and resulted in estimating the crystal-field splitting Δ = E(Γ₈) - E(Γ₇) of the lowest ²F_5/2 manifold for Ce³⁺ ions in PbA (A = S, Se and Te) of about 340 K, 440 K and 540 K for Pb_1-xCe_xTe, Pb_1-xCe_xSe, and Pb_1-xCe_xS, respectively. The values for the crystal-field splitting deduced from the magnetic data were found to be in agreement with the calculated ones based on the point charge model. Moreover, the deHaas van-Alphen magnetic oscillations in the susceptibility measurements of Pb_1-xCe_xTe (x~ 0.05 and 0.07) were observed at ultra-low temperature (20 mK); The oscillations were investigated and the values of the oscillatory period for Pb_1-xCe_xTe (x = 0.0048 and 0.007) are reported.