Transport, thermoelectric, and thermal expansion investigations of the cage structure compound CeOs2Al10

Abstract

In order to shed light on the electrical and thermal properties of the cage-type CeOs 2 Al 10 , we investigate this material by measuring electrical resistivity, Seebeck coefficient, thermal conductivity, specific heat, and thermal expansion. The phase transition T 0 ∼ 28 K for CeOs 2 Al 10 has been characterized by marked features in all measured physical quantities. Above T o , the electrical resistivity and Seebeck coefficient can be well described by a two-band model with reliable physical parameters. Furthermore, the extracted magnitude of the quasielastic linewidth q f ∼ 30.2 K is found to be consistent with that observed in the neutron scattering experiment. These results are compared to its isostructural compound CeRu 2 Al 10 .

Contrasting effect of La substitution on the magnetic moment direction in the Kondo semiconductorsCeT2Al10(T=Ru,Os)

“…The resistivity of CeRu 2 Al 10 exhibits a sharp drop near 27 K resembling an insulator-metal transition [2]. A very similar phase transition, near 29 K, has been observed in CeOs 2 Al 10 [8,14], but in this compound the susceptibility (along the a−axis) exhibits a broad maximum near 45 K in contrast to a sharp drop at the phase transition * Electronic address: devashibhai.adroja@stfc.ac.uk (27 K) in CeRu 2 Al 10 [8,15]. The broad maximum in the susceptibility and its strong anisotropic behavior in the paramagnetic state reveal the presence of strong hybridization between 4f and conduction electrons as well as strong single ion anisotropy arising from the crystal field potential [16,17].…”

“…the ρ(T ) shows a slope change at T N , but still increases with further decrease in the temperature down to 2 K. This contrasting behavior of the low temperature resistivity is similar to that observed in the undoped compounds [14,15]. It is interesting to note that the resistivity of slightly electron-(8% Ir) and hole-(2% Re) doped CeOs 2 Al 10 exhibits metallic behavior in all directions below T N [24].…”

Magnetic instability induced by Rh doping in the Kondo semiconductor CeRu2Al10

“…In order to analyze these spectra, we use the function of is the Kubo-Toyabe function, 24 usually used to describe the μSR spectrum in the randomly oriented static internal fields with Gaussian distribution, which originates from the nuclear dipole moments of Ru ( 99 Ru, I = 3/2, 12.72% abundance; 101 Ru, I = 5/2, 17.07% abundance), 27 Al (I = 5/2), and 103 Rh (I = 1/2) in this case. A(0) is the initial asymmetry at t = 0, /γ μ represents the distribution width of the local fields, γ μ /2π = 13.55 MHz/kOe is the gyromagnetic muon ratio, and λ is the depolarization rate caused by fluctuating electronic spins.…”

Field-insensitive heavy fermion features and phase transition in the caged-structure quasi-skutterudite Sm3 Ru4 Ge13

“…From the fit, q f ≈ 25 K is obtained. A similar value of 30 K was obtained in the case of another caged structure compound, CeOs 2 Al 10 [48]. The two-band model is not valid across the phase transition and hence fails to explain the region of ρ(T ) below about 40 K. The isothermal magnetoresistance, ρ(H), of Sm 3 Ru 4 Ge 13 at 2, 5 and 10 K are presented in (c).…”

“…An activated-type of resistivity behaviour was observed in many R 3 T 4 X 13 systems [47] hence, an analysis using ρ = ρ 0 [1 + exp(-∆/2T )] was attempted. However, the fit deviated from the data at about 60 K and yielded a ∆ value of 473.4(8) K. The ∆ value is comparable to that obtained for Y 3 Ir 4 Ge 13 [25] but is vastly different from systems like CeOs 2 Al 10 [48]. A curve-fit assuming ρ ∼ -ln (T) pertinent to a Kondo system was attempted to find that the linear region extends over a significant range from 300 K to about 60 K. However, magnetoresistance data (shown later) rules out the presence of Kondo effect.…”