ON THE MAGNETIC-STRUCTURE OF ER2FE14SI2

Elastic powder neutron diffraction experiments on the off-stoichiometr ic Th2Ni17-type Er2Fe14Si2 have been performed at temperatures between 10 and 593 K. In the paramagnetic state, a structural refinement reve aled only small deviations from the statistical occupation of Fe on al l four lattice sires. In the magnetically ordered state below T-c = 47 8 K, a magnetic refinement was performed, too, Above the upper spin re orientation temperature T-sr1 = 110 K, a simple ferrimagnetic structur e with an easy plane magnetization was found. In the temperature range T-sr1 = 110 K and T-sr2b = 30 K the moments tilt out of the plane. Be low 30 K the magnetization is again easy plane, but with reduced Er mo ments. At ambient temperature, neutron diffraction experiments have be en performed on the stoichiometric pseudobinary compound Er2Fe1.5Si2 t oo, in order to look for some influence of the deviation From the exac t stoichiometry on the formation of the magnetic moments. (C) 1998 Els evier Science B.V. All rights reserved.