The Heusler phases LiRh2Si and LiRh2Ge: Synthesis, structure and properties

The isostructural Heusler phases LiRh2Si and LiRh2Ge have been synthesized from the elements and an excess of lithium at 1000 °C. Both materials adopt the CuMn2Al crystal structure, space group Fm−3m (No. 225) with the room temperature lattice parameter a=5.747(1) Å [Vol=189.866(1) Å3] and a=5.847(1) Å [Vol=199.88(6) Å3] for LiRh2Si and LiRh2Ge, respectively. X-ray analyses suggest mixed site occupancy of the form Li1−xRh2Si1+x (x<0.4), but not for LiRh2Ge. Both materials are diamagnetic, χmol(LiRh2Si)=−6×10−5 cm3(mole)−1 and χmol(LiRh2Ge)=−10×10−5 cm3(mole)−1 and metallic with room temperature resistivities of approximately 19 and 32 μΩ cm, respectively. These properties are consistent with the calculated electronic structure.

Rh, Li and either Si or Ge form an ordered coloring pattern of the bcc lattice in the Heusler phases LiRh2Si and LiRh2Ge. Crystals grown from a reactive Li flux are diamagnetic metals that exhibit a T-linear resistivity above 60 K.Figure optionsDownload as PowerPoint slide