Anomalous low-temperature behavior of PrT2B2C and

Pressure effects in PrT2B2C (T = Co, Ni, Pt): Applied and chemical pressure

“…In an opposite way to PrNi 2 B 2 C, the low‐temperature curvature of $\rho _{ab} (T)$ , which is also associated with magnetic correlations, tends strongly to be suppressed by pressure. This tendency has also been observed by Massalami et al 37 by applying pressures up to about 1.2 GPa, the maximum pressure value they applied. Similar to their results, we also observed that the quadratic behavior of $\rho _{ab} (T)$ at low temperatures is maintained under 1.2 GPa.…”

“…Thus, in a similar compound but simpler, RCo 2 , a T 2 dependence has been found at low temperatures, which is due to spin fluctuation characteristics 28. The fact that the magnitude of the quadratic coefficient A of ρ ( T ) for PrCo 2 B 2 C is of the order of that for RCo 2 (Massalami et al 37 found this coefficient as big as three orders of magnitude but in polycrystalline PrCo 2 B 2 C) suggests that spin fluctuations could be the responsible mechanism for the low temperature ρ ( T ) behavior in this compound. Using the universal relation for heavy fermion compounds, $A/\gamma {}^{2} = 1.0\; \times \;10^{{-} 5} \;\mu \Omega {\rm cm}({\rm mol}\,{\rm K})^{2} /{\rm mJ}^{2} $ 38, the resulting Sommerfeld coefficient is γ = 89.4 mJ/mol K 2 , which is a low value compared with that for PrNi 2 B 2 C (211 mJ/mol K 2 26 by specific heat measurements), but an enhanced value as compared to the normal metal Co and to other borocarbides such as YCo 2 B 2 C 11 and (Gd, Tb, Dy, Ho, Er, Tm)Ni 2 B 2 C 39, whose γ is about 17 mJ/mol K 2 .…”

Theoretical study of the electronic properties ofPrM2B2C(M=Galván1, Durán2, Amarillas3 et al. 2006Phys. Rev. B5110View full textAdd to dashboardCite

“…1,13,14,25 An appreciable hybridization between the admixture of −d, −p states crossing the E F for Pr/ Ni and Pr/ Co compounds and the enhancement of the −f band contribution with respect to the superconductor Lu/ Ni, where in the latter compound the Lu −f contribution only reaches 0.55%, 5 is manifested by the different experimental transport properties. 12,13 For example, the resistivity ͑͒ as a function of temperature is linear down to ϳ100 K ͑metallic charac-ter͒. with major slope ͑d /dT͒ values for Pr/ Co compounds.…”

“…12,13 On the other hand, the replacement of M by Pt induces significant changes in the internal crystal structure, with superconductivity present at about 6 K without magnetic ordering down to 1.8 K. In addition, specific heat measurement shows a slight enhancement in the Sommerfeld constant ͑␥͒ with respect to that of LuNi 2 B 2 C compound. 14 In this work, we have employed previous structural data extracted from single crystals in order to study the electronic structure of PrM 2 B 2 C ͑T = Ni, Co, and Pt͒ using Huckel tight-binding calculations.…”

IsomorphousPrT2B2C(T=CoDurán1, Bernès2, Falconi3 et al. 2006Phys. Rev. B71130View full textAdd to dashboardCite

“…In this family, the compounds formed with Pr͑Ni, Co͒ 2 B 2 C show long range magnetic ordering and superconducting behavior for the case of PrPt 2 B 2 C compound. [11][12][13] It is worth mentioning that there are only a few praseodymium based compounds that present superconductivity; that is, among the high T c ceramic superconductors, only those with partial substitutions of praseodymium in the TЈ phase ͑R 2 CuO 4 ͒ have been found superconducting while in the PrBa 2 Cu 3 O 7−x compound the possibility of superconductivity is still questioned and is under discussion. 14,15 However, superconductivity has been found in the following intermetallic systems; PrMo 6 ͑S,Se͒ 8 compounds ͑T c ϳ 4, and 9 K͒, 16 borocarbide PrPt 2 B 2 C ͑T c ϳ 6 K͒, 11 and recently in the PrOs 4 Sb 12 which is a heavy fermion skutterudite with T c ϳ 1.8 K. 17 Under this scenario a systematic study of the changes observed in structural and electronic properties for PrT 2 B 2 C ͑T = Ni, Co, and Pt͒ single crystals is presented.…”