<sup>169</sup>Tm Mossbauer investigation of thulium pyrogermanate
G A Stewart; J M Cadogan; A V J Edge; G A Stewart; Dept. of Phys., South Wales Univ., Campbell, ACT, Australia; J M Cadogan; Dept. of Phys., South Wales Univ., Campbell, ACT, Australia; A V J Edge; Dept. of Phys., South Wales Univ., Campbell, ACT, Australia
Журнал:
Journal of Physics: Condensed Matter
Дата:
1992-02-17
Аннотация:
A <sup>169</sup>Tm Mossbauer investigation of thulium pyrogermanate is reported. All spectra recorded over the temperature range 4.2 K-740 K are pure quadrupole doublets. This observation and the detailed temperature dependence of the quadrupole interaction are inconsistent with recent claims of a fivefold local symmetry at the Tm<sup>3+</sup> site. Initial attempts at analysing the data in terms of the full crystal-field Hamiltonian appropriate for C<sub>1</sub> symmetry suggest that the electronic ground state consists of a pair of non-magnetic singlets well isolated from the next state.
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