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arXiv · 1001.3329

Gd3+ rattling triggered by a "weak" M-I transition at 140-160 K in the Ce1-xGdxFe4$P12 x ~ 0.001 skutterudite compounds: an ESR study

F. A. Garcia·J. G. S. Duque·P. G. Pagliuso·C. Rettori·Z. Fisk·S. B. Oseroff
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Abstract

In this work we report electron spin resonance (ESR) measurements in the semiconducting Ce1-xGdxFe4P12 (x ~ 0.001) filled skutterudite compounds. Investigation of the temperature (T) dependence of the ESR spectra and relaxation process suggests, that in the T-interval of 140-160 K, the onset of a "weak" metal-insulator (M-I) transition takes place due to the increasing density of thermally activated carriers across the semiconducting gap of ~ 1500 K. In addition, the observed low-T fine and hyperfine structures start to collapse at ~ 140 K and is completely absent for > 160 K. We claim that the increasing carrier density is able to trigger the rattling of the Gd3+ ions which in turn is responsible, via a motional narrowing mechanism, for the collapse of the ESR spectra.

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F. A. Garcia, J. G. S. Duque, P. G. Pagliuso, C. Rettori, Z. Fisk, S. B. Oseroff. 2010-01-19. Gd3+ rattling triggered by a "weak" M-I transition at 140-160 K in the Ce1-xGdxFe4$P12 x ~ 0.001 skutterudite compounds: an ESR study. https://doi.org/10.1002/pssb.200983015

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