CRYSTALLOGRAPHIC AND MAGNETIC-PROPERTIES OF CU2FEGESE4 AND CU2FEGETE4COMPOUNDS

X-ray powder diffraction measurements, at room temperature, and magnet ic susceptibility chi measurements, in the temperature range from 2 to 300 K, were made on polycrystalline samples of Cu2FeGeSe4 and Cu2FeGe Te4 magnetic semiconductor compounds. Magnetization measurements at 2, 4.2 and 77 K in magnetic fields up to 35 T were carried out on Cu2FeG eSe4 compounds. From the analysis of the X-ray diffraction lines, it w as found that Cu2FeGeSe4 and Cu2FeGeTe4 have, respectively, stannite a nd monoclinic structures. The resulting 1/chi versus T curves showed t hat Cu2FeGeSe4 is antiferromagnetic with a Neel temperature T-N = 20 K while Cu2FeGeTe4 is ferri-magnetic with T-N = 160.1 K. The magnetizat ion and susceptibility results obtained on Cu2FeGeSe4 showed the prese nce of bound magnetic polarons (BMPs) in agreement with earlier studie s made on this type of materials [1, 2].