To improve the thermoelectric properties of LaCeFe3CoSb12 skutterudite materials, the LaCeFe3CoSb12 nanopowders of disordered structure were fabricated through a laser melting and quenching process and then were hot pressed into bulk pellets with the coexistence of ordered and disordered structures by mixing the disordered powders with the raw LaCeFe3CoSb12 crystalline materials. The results suggest that the introduced disordered structure can increase Seebeck coefficient from 57 to 179 μV/K while reduce thermal conductivity from 3.1 to 1.5 W/(m·K), although electrical conductivity can be decreased from 98,000 to 43,000 S/m, and consequently, figure of merit can be enhanced from 0.11 to 0.90 at 773 K. Therefore, fabricating a material with the coexistence of disordered and ordered structures can be considered as an effective way to obtain a high figure of merit, and this strategy can be also applied to other thermoelectric alloys.

Crystal structure and structural disorder of Ba3MgSi2O8 were reinvestigated by laboratory X-ray powder diffraction. The title compound was found to be trigonal with space group P3m1, Z=1, and unit-cell dimensions a=0.561 453(4) nm, c=0.727 629(4) nm, and V=0.198 641(2) nm3. The initial structural model used for structure refinement was taken from that of glaserite (K3NaS2O8) and modified by a split-atom model. In the split-atom model, one of the two types of Ba sites and that of SiO4 tetrahedra were, respectively, positionally and orientationally disordered. The new crystal structure and structural disorder were refined by the Rietveld method. The maximum-entropy-method-based pattern fitting (MPF) method was used to confirm the validity of the split-atom model, in which conventional structure bias caused by assuming intensity partitioning was minimized. The final reliability indices calculated from MPF were Rwp=6.52%, S=1.36, Rp=4.84%, RB=0.97%, and RF=0.52%. Details of the disorder structure of Ba3MgSi2O8 are shown in the three-dimensional and two-dimensional electron-density distribution maps determined by MPF.