Cation distribution and crystallographic characterization of the quaternary spinel system Mg Co1−Cr Fe2−O4

Neutron diffraction studies of the magnetic ordering in the spinel oxide system Mg Co1−Cr Fe2−O4

“…In view of that the quaternary spinel system Mg x Co 1−x Cr x Fe 2−x O 4 (x = 0.0, 0.25, 0.50, 0.75 and 1.0) was chosen for neutron diffraction study as functions of composition as well as temperature to have a clear understanding of the magnetic ordering in such a doubly substituted system. Our cation distribution study on the system reported recently [20] showed that the B site has become highly inhomogeneous in respect of magnetic ion concentration due to the presence of three types of magnetic ions (Cr 3+ , Fe 3+ and Co 2+ ) differing in strength of their magnetic moments and at the same time by the presence of the majority of nonmagnetic Mg 2+ ions. Shukla et al [21] reported the structural and magnetic properties of the system Mg x Co 1−x FeCrO 4 (x = 0.0, 0.1, 0.2, 0.3, 0.4, 0.5 and 0.6) based on X-ray diffraction, magnetization, ac susceptibility and Mössbauer spectroscopy analysis.…”

“…Neutron diffraction data from all the five compositions containing both nuclear and magnetic contributions were refined in the Rietveld method using the software package FullProf [22]. The cation occupancies determined from our previous study [20] listed in Table 1 were used in the refinement and were kept fixed and the rest of the refinement parameters were varied freely. All the data were refined to convergence and the results were decided on the basis of the best agreement factors.…”

“…The details of the preparation of samples have been reported elsewhere [20]. Neutron powder diffraction measurements on all the samples were performed at a number of temperatures in the range 10-810 K using the high resolution powder diffractometer (HRPD) located at the 1G beam port of JRR3 reactor of Japan Atomic Energy Agency (JAEA), Tokai, Japan.…”

Rietveld analysis using powder diffraction data with anomalous scattering effect obtained by focused beam flat sample method

“…A Rietveld refinement program, PFLS.exe [12] were used for structure refinements. The crystal structure model was taken from single crystal analyses (2008) [13,14], which has a cubic structure with the space group of Fd3m(227) at room temperature. Atomic scattering factors of Co 2+ , Fe 3+ and O 2- [15] were applied and anomalous scattering factors of Co and Fe metals were taken from Sasaki (1989) [8].…”

Formation and properties of BaxFe3−xO4 with spinel structure by mechanochemical reaction of α-Fe2O3 and BaCO3

“…Cations incorporated in spinel lattice change magnetic interactions and magnetic anisotropy, influencing the saturation magnetization and coercivity values of parent compounds [5] such as, Ni, Zn [6,7], Ho [8], Li [9], Mg [10,11] and so on. Ba element is recently considered as a good candidate for changing magnetic properties of ferrite recently, for example, it makes the soft magnetic or nonmagnetic ferrite change into hard magnetic barium ferrite.…”