The magnetization and specific heat of single-crystalline samples of filled-skutterudite compounds YbxFe4Sb12 were measured. Six single crystals with the filling ratio of Yb, x, from 0.875 to 0.910 were prepared. The weak ferromagnetism of YbxFe 4Sb12 appearing at low temperatures was found to strongly correlate with x; with increasing x from 0.875 to 0.910, the transition temperature, TC, decreases from 17 to 5K and the weak-ferromagnetic moment, m0, decreases from 0.066 to 0.005μB/Fe. From these trends, both TC and m0 were expected to reach zero at the critical concentration, xc = 0.93. In the temperature dependence of the specific heat, no anomaly at TC was observed, reflecting that m0 is extremely small compared with the effective Bohr magneton number. With the application of pressure, the TC of the sample with x = 0.882 increases rapidly, with the ratio of dTC/dP = +5:27 K/GPa. This weak ferromagnetism of YbxFe4Sb12 originates from the itinerant 3d electrons of Fe in anions [Fe 4Sb12].
All Science Journal Classification (ASJC) codes
- General Physics and Astronomy