Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1606384 | Journal of Alloys and Compounds | 2016 | 8 Pages |
Abstract
The robust field-insensitive heavy fermion features in Sm3 Ru4 Ge13 and the magnetic phase transition at TN â 5 K are studied using magnetization M(T), specific heat Cp(T), resistivity Ï(T) and thermal conductivity κT(T). The average crystal structure of Sm3 Ru4 Ge13 conforms to the cubic space group Pm3¯n however, signatures of subtle structural distortions are obtained from the x ray data. The magnetic susceptibility, Ï(T), follows a modified Curie-Weiss law indicating the presence of crystal fields of Sm3+ and the significance of van Vleck terms. No sign of ferromagnetism is observed in M(H) of Sm3 Ru4 Ge13 which yields only 0.025 μB/f.u.-Sm at 2 K, 7 T. The Sommerfeld coefficient, γâ 220 mJ/mol-Sm K2, estimated from the analysis of low temperature specific heat suggests the formation of heavy quasi particles at low temperature. Though a lnT dependence of Ï(T) is observed till 60 K, the resistivity behavior is accounted for by assuming a two-band model for activated behavior of charge carriers. The field scans of resistivity, Ï(H), below TN display significant nonlinearity while those above the TN are more metal-like. Low values of thermal conductivity, κT(T), are observed in Sm3 Ru4 Ge13 however, displaying an anomaly at TN which signifies magnetoelastic coupling. A fairly high value of Seebeck coefficient, S â 40 μV/K is observed at 300 K. We identify Sm3 Ru4 Ge13 as a low charge carrier density system with unusual field-insensitive heavy fermion features very similar to the filled skutterudites.
Keywords
Related Topics
Physical Sciences and Engineering
Materials Science
Metals and Alloys
Authors
Harikrishnan S. Nair, Ramesh Kumar K., Douglas Britz, Sarit K. Ghosh, Christian Reinke, André M. Strydom,