Valence fluctuation in Ce$_{2}$Co$_{3}$Ge$_{5}$ and crystal field effect in Pr$_{2}$Co$_{3}$Ge$_{5}$

Samar Layek; V. K. Anand; Z. Hossain

doi:10.1016/j.jmmm.2009.06.039

paper

Valence fluctuation in Ce $_{2}$ Co $_{3}$ Ge $_{5}$ and crystal field effect in Pr $_{2}$ Co $_{3}$ Ge $_{5}$

arXiv:0908.3880 · doi:10.1016/j.jmmm.2009.06.039

Abstract

Polycrystalline samples of ternary rare earth germanides R $_{2}$ Co $_{3}$ Ge $_{5}$ (R = La, Ce and Pr) have been prepared and investigated by means of magnetic susceptibility, isothermal magnetization, electrical resistivity and specific heat measurements. All these compounds crystallize in orthorhombic U $_{2}$ Co $_{3}$ Si $_{5}$ structure (space group \textit{Ibam}). No evidence of magnetic or superconducting transition is observed in any of these compounds down to 2 K. The unit cell volume of Ce $_{2}$ Co $_{3}$ Ge $_{5}$ deviates from the expected lanthanide contraction, indicating non trivalent state of Ce ions in this compound. The reduced value of effective moment ( $μ_{e f f}$ $\approx$ 0.95 $μ_{B}$ ) compared to that expected for trivalent Ce ions further supports valence fluctuating nature of Ce in Ce $_{2}$ Co $_{3}$ Ge $_{5}$ . The observed temperature dependence of magnetic susceptibility is consistent with ionic interconfiguration fluctuation (ICF) model. Although no sharp anomaly due to a phase transition is seen, a broad Schottky-type anomaly is observed in the magnetic part of specific heat of Pr $_{2}$ Co $_{3}$ Ge $_{5}$ . An analysis of $C_{ma g}$ data suggests a singlet ground state in Pr $_{2}$ Co $_{3}$ Ge $_{5}$ separated from the singlet first excited state by 22 K and a doublet second excited state at 73 K.

12 pages, 5 figures

Valence fluctuation in Ce $_{2}$ Co $_{3}$ Ge $_{5}$ and crystal field effect in Pr $_{2}$ Co $_{3}$ Ge $_{5}$

Abstract

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Valence fluctuation in Ce2​Co3​Ge5​ and crystal field effect in Pr2​Co3​Ge5​

Abstract

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Cited by in corpus (6)

Valence fluctuation in Ce $_{2}$ Co $_{3}$ Ge $_{5}$ and crystal field effect in Pr $_{2}$ Co $_{3}$ Ge $_{5}$