The magnetic heat capacity in the form of Cm/T exhibits a maximum and substantially decreases at low temperatures, suggesting the energy gap opening in the heavy quasiparticle band [330]. A broad maximum about 113 K seen in the magnetic susceptibility data, which suggests valence fluctuation in Ce of this compound [331]. Malik et al. [332] reported that ΔC/T (ΔC =magnetic heat capacity) shows a maximum at 10 K (Tmax) and is linear below it. The linear nature of ΔC/T below 10 K, which is the gapped state, is attributed to the decrease in electronic DOS with decrease in temperature [332].In CeRhBi, the analysis of heat capacity data provides large γ, which is 500 mJ/mol K2 and reveals heavy fermion behavior of this system [333]. Occurance of magnetic ordering and gap formation in CeRhBi compound has been ruled out by electrical resistivity and 209Bi- NQR measurements [333]. The magnetic susceptibility data obeys Curie Weiss law above 70 K, while the susceptibility is temperature independent up to 250 K in CeRhAs [333]. It has been observed that suppression of gap in CeRhAs take place on the application of external pressure, which may be due to the opposite effect of chemical and the external pressure on the gap size [333]. In addition to this, CeRhAs shows mixed valent semiconductor behavior with an energy gap of 144 K, which is much larger than that of CeRhSb [333].
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