E. Maciążek

Effect of Cation Substitution on Critical Fields in the n-type Zn_{x}Sn_{y}Cr_{z}Se_{4} Spinel Semiconductors

The ac dynamic magnetic susceptibility was used to study a cation substitution on critical fields in polycrystalline (Zn0.87Sn0.048)Cr2.02Se4 and Zn0.93[Cr1.95Sn0.05]Se4 spinels with tetraand octahedral coordination of Sn ions, respectively. An increasing static magnetic field shifts the Néel temperature TN to lower temperatures while a susceptibility peak at Tm in the paramagnetic region — to higher temperatures. Below TN the magnetic field dependence of susceptibility, χac(H), shows two peaks at critical fields Hc1 and Hc2. The values of Hc1 decrease slightly with temperature while the values of Hc2 decrease strongly with temperature, especially for spinel with octahedral coordination of Sn ions, suggesting a weakness of the ferromagnetic component.

X-Ray Analysis of New Gadolinium Doped CuCr2Se4

Abstract. Phase and structure analysis of CuCr2-xGdxSe4 (x=0.1÷0.3) synthesized using a solid state reaction method were carried out using X-Ray powder diffraction. All obtained compounds were found to be multi phase with the spinel phase being dominant up to x=0.1, indicating low solubility limit of gadolinium. Two compounds CuCr1.95Gd0.05Se4 and CuCr1.9Gd0.1Se4,. were chosen for a detailed structure refinement.