Spin dynamics of S-state ions in the filled skutterudites La1-xRx$Pt4Ge12 (R= Gd, Eu)

Abstract

A detailed study of the spin dynamics of the S-state ions Gd3+ and Eu2+ in the filled skutterudites La1-xRxPt4Ge12 (R= Gd, Eu) is reported. The spin dynamics is investigated directly by means of Gd3+ and Eu2+ electron spin resonance (ESR), performed at X-band (~ 9.4 GHz) and Q-band (~ 34 GHz) frequencies in the temperature intervals 8<T<300 K and 1.5<T<300 K respectively. The ESR parameters provide direct evidence for the vibrational behavior of the Gd3+ ions but not for the Eu2+ ions. These results are interpreted in the light of recent discussions about the spin relaxation in cage systems. In particular, the Gd3+ spin relaxation in La0.9Gd0.1Pt4Ge12 provide evidence for the existence of an extra phonon mode with an Einstein temperature (thetaE) ~ 24 K in this system. The work suggests that the so-called "rattling" modes have a general and important role that should be taken into account in the study of spin dynamics in cage systems.

8 pages, 8 figures

References in corpus (7)

• Superconductivity in the New Platinum Germanides MPt4Ge12 (M = Rare-earth and Alkaline-earth Metals) with Filled Skutterudite Structure
• NMR relaxation and resistivity from rattling phonons in pyrochlore superconductors
• Low-lying excitations at the rare-earth site due to rattling motion in the filled skutterudite LaOs_4Sb_{12} revealed by ^{139}La NMR and ^{121/123}Sb NQR
• Strong-Coupling Theory of Rattling-Induced Superconductivity
• Kondo Effect of a Magnetic Ion Vibrating in a Harmonic Potential
• Magnetic order in the filled skutterudites RPt4Ge12 (R = Nd, Eu)
• Eu2+ spin dynamics in the filled skutterudites EuM4Sb12 (M = Fe, Ru, Os)

Cited by in corpus (3)

• Investigation of superconducting and normal-state properties of the filled-skutterudite system PrPt${}_4$Ge${}_{12-x}$Sb${}_x$
• Collapse of the $G{d}^{3+}$ ESR fine structure throughout the coherent temperature of the Gd-doped Kondo Semiconductor $CeF{e}_4{P}_{12}$
• Vibrational and structural properties of the $R$Fe${}_4$Sb${}_{12}$ ($R=$Na, K, Ca, Sr, Ba) filled skutterudites