Synthesis and structural characterization of the magnetic semiconductor silver iron germanium selenide (Ag2FeGeSe4)

The quaternary semiconductor compound Ag2FeGeSe4, belonging to the system I2-II-IV-VI4 and synthesized by the melt and anneal technique, was structurally characterized by Rietveld refinement of the powder X-ray diffraction data. This compound crystallizes in the orthorhombic space group Pmn21, Z = 4, with unit cell parameters a = 7.6478(1) ??, b = 6.5071(1) ??, c = 6.4260(1) ??, and V = 319.79(1) ??3, in a wurtzite-stannite arrangement with a Cu2CdGeS4-type structure. The Debye temperature (???D) estimated for this compound was 194 K.