Electron paramagnetic resonance investigations of Gd3+ in Cs2NaYCl6 in the6-473 K temperature range

Electron Paramagnetic Resonance (EPR) studies of cesium sodium yttrium hexa chloride (Cs2NaYCl6), doped with trivalent gadolinium ions in the 6-473 K t emperature range are presented in this work. Owing to the fact that Gd3+ is located in a cubic crystalline electric field (CEF) symmetry, the relevant spin-Hamiltonian parameters are g, b(4)(o) and b(6)(o). It is then establi shed the temperature dependence of b(4)(o). The absolute sign of b(4)(o) is determined upon comparing the relative intensity of the otherwise equivale nt outermost transitions of the EPR spectrum registered at 6 K. Values of g and b(6)(o) are also reported. Anomalous changes in line-width upon reduci ng the temperature are also discussed in terms of the thermal constriction of the lattice, and its repercussion on the modified Goldsmith tolerance fa ctor (GTF) value. (C) 1999 Elsevier Science Ltd. All rights reserved.