Effect of rare earth filling on unfilled skutterudite compound CoSb3

Abstract We have succeeded in synthesizing the filled skutterudite compound Pr x Co 4 Sb 12 under high pressures. Pr site filling factor was estimated to be about 50 ± 10% by powder X-ray diffraction and chemical composition analysis using field emission electron microscope. Apparent expansion of lattice constant 9.09 A compared to that of CoSb 3 9.03 A is also indirect evidence of successful filling of Pr-ions. In the magnetization and specific heat measurements, no anomaly suggesting phase transition has been found down to 2 K.