Synthesis and structural characterization of Bi₂O₃-M₂O₃ (M=Dy and Pr) binary systems

912-915The binary systems Bi2O3-Dy2O3 and Bi2O3-Pr2O3 have been investigated by doping Dy2O3 and Pr2O3 in the composition range 10 - 40 mole % prepared by ceramic method. From the phase evolution studies of Dy2O3 doped samples, it was observed that fluorite structured f c c phase is stabilized for the composition range 10-40 mole %. The stability of d- phase was affected by the heat treatment temperatures. The higher the content of dopant concentration, the higher was the sintering temperature. The lattice parameter for Dy2O3 doped samples decreased with the increase of dopant concentration and obeyed Vegard’s rule. From the structural studies of Pr2O3 doped samples rhombohedral phase was found for 10 to 30 mole % of dopant concentrations. For 40 mole % of dopant concentration, the impurity peaks were observed in the XRD patterns along with rhombohedral phase. The unit cell parameters for Pr2O3 doped samples were evaluated on hexagonal settings

Study of <span style="font-size:14.0pt;line-height:115%; font-family:"Times New Roman";mso-fareast-font-family:HiddenHorzOCR;color:black; mso-ansi-language:EN-IN;mso-fareast-language:EN-IN;mso-bidi-language:HI" lang="EN-IN">bulk <span style="font-size:14.0pt;line-height:115%;font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman";color:black;mso-ansi-language:EN-IN; mso-fareast-language:EN-IN;mso-bidi-language:HI" lang="EN-IN">magnetic properties of the mixed spinel MgCr_xFe_2-xO₄</span></span>

226-230<span style="font-size:14.0pt;line-height: 115%;font-family:" times="" new="" roman";mso-fareast-font-family:"times="" roman";="" color:black;mso-ansi-language:en-in;mso-fareast-language:en-in;mso-bidi-language:="" hi"="" lang="EN-IN">The polycrystalline samples of the mixed spinel series MgCrxFe2-xO4 with x = 0.0, 0.2, 0.4, 0.6, 0.8, 1.0 have been prepared in the pellet form by standard ceramic technique and were studied by means of X-ray diffraction, magnetization and ac susceptibility measurements. The X-ray analysis shows that the samples are formed in a single-phase spinel structure. The lattice parameter a obtained from X-ray data increases initially upto x = 0.4, and thereafter it decreases. The variation of the saturation magnetic moment per formula unit measured at 300K decreases with Cr content x. The ac susceptibility was measured from room temperature to 680 K. The Curie temperature obtained from ac susceptibility measurements decreases nearly linearly with the increase of Cr content x, suggesting the decrease in ferrimagnetic <span style="font-size:14.0pt;line-height:115%; font-family:" times="" new="" roman";mso-fareast-font-family:hiddenhorzocr;color:black;="" mso-ansi-language:en-in;mso-fareast-language:en-in;mso-bidi-language:hi"="" lang="EN-IN">behaviour.</span