Anand, V. K.; Adroja, D. T.; Idczak, R.; Bhattacharyya, A.; Tripathi, R.; Tran, V. H.; Lake, B.: Thermal conductivity, thermoelectric power and Mossbauer investigations on antiferromagnetic CeFe1.7Ir0.3Al10. Journal of Magnetism and Magnetic Materials 556 (2022), p. 169370/1-7
10.1016/j.jmmm.2022.169370
Abstract:
CeFe2Al10 is known to exhibit a Kondo semiconducting behavior without any signature of long range magnetic ordering. A partial Ir substitution for Fe in CeFe2Al10 is found to drive the system towards long range magnetic ordering, and a 15% Ir substitution is found to result in an antiferromagnetically ordered state below 3.1(2) K in CeFe1.7Ir0.3Al10. We present the results of the electrical resistivity rho, thermal conductivity kappa and thermoelectric power S measurements as a function of temperature T, and Fe-57 Mossbauer spectroscopy on polycrystalline CeFe1.7Ir0.3Al10. The rho(T) exhibits Kondo lattice behavior and presents evidence for the formation of a superzone gap in antiferromagnetic state. We estimate Kondo temperature T-K approximate to 18 K. The kappa(T) does not show any anomaly and reflects a phonon dominated thermal transport. The Lorenz number L(T) = kappa(T)rho(T)/T is found to be much larger than the theoretical Sommerfeld value L-0 which also reflects a phonon dominance. The S(T) exhibits a minimum at low T(S-min approximate to -2.3 mu V/K, T-Smin approximate to 30 K) and a maximum at high T (S-max 5.4 mu V/K, T-smax approximate to 225 K). The S(T) data are described by a two-band model with contributions from two Lorentzian shaped f-bands. From the analysis of S(T), we infer that while one of the contributing f-band lies 22 K below the Fermi energy E-F, the other one is at 190 K above E-F. The Fe-57 Mossbauer spectra collected in zero field do not show clear evidence of magnetic ordering, however, the Mossbauer measurements in external fields support an antiferromagnetic ordering in CeFe1.7Ir0.3Al10.