Distortion of the crystal field in the van Vleck paramagnet LiTmF 4 activated by isovalent impurities

The spin‐lattice relaxation times of Ce 3+ , Nd 3+ , Yb 3+ ions are measured in LiTmF 4 single crystals at temperatures (1.6 to 5.0 K) and frequencies 9.4 and 23.0 GHz. An observed exponential dependence of the relaxation rate on temperature, T ∼ exp (−Δ/ kT ), shows that relaxation proceeds through...

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Veröffentlicht in:physica status solidi (b) 1989-03, Vol.152 (1), p.191-201
Hauptverfasser: Aminov, L. K., Vinokurov, A. V., Kurkin, I. N., Kostetskii, Yu. Yu, Korableva, S. L., Salikhov, I. Kh, Sakhaeva, S. I., Teplov, M. A.
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Sprache:eng
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Zusammenfassung:The spin‐lattice relaxation times of Ce 3+ , Nd 3+ , Yb 3+ ions are measured in LiTmF 4 single crystals at temperatures (1.6 to 5.0 K) and frequencies 9.4 and 23.0 GHz. An observed exponential dependence of the relaxation rate on temperature, T ∼ exp (−Δ/ kT ), shows that relaxation proceeds through Van Vleck Tm 3+ host ions, and for the Nd 3+ ion it is possible to distinguish the contributions to relaxation of the nearest and more distant coordination spheres. The distinction of the activation energy Δ from the excitation energy of the lowest Tm 3+ doublet state in the ideal crystal ( 32 cm −1 ) is explained by a strong distortion of the crystal field at the Tm 3+ ions nearest to the impurity. Investigations of the optical absorption spectra of Tm 3+ ions in pure and doped LiTmF 4 single crystals are in good agreement with this point of view. [Russian Text Ignored].
ISSN:0370-1972
1521-3951
DOI:10.1002/pssb.2221520121