Jump to main content
Jump to site search

Issue 31, 2017
Previous Article Next Article

Cation distribution dependent magnetic properties in CoCr2−xFexO4 (x = 0.1 to 0.5): EXAFS, Mössbauer and magnetic measurements

Author affiliations

Abstract

In this report, we have examined the evolution of the structure and rich magnetic transitions such as a paramagnetic to ferrimagnetic phase transition at the Curie temperature (TC), spiral ordering temperature (TS) and lock-in temperature (TL) observed in the CoCr2O4 spinel multiferroic after substituting Fe. The crystal structure, microstructure and cation distribution among the tetrahedral (A) and octahedral (B) sites in the spinel lattice are characterised by X-ray diffraction, transmission electron microscopy, Extended X-ray Absorption Fine Structure (EXAFS) and Mössbauer spectroscopy. Due to the same radial distances of the first coordination shell in both tetrahedral and octahedral environments observed in EXAFS spectra, the position of the second coordination shell specifies the preference of more Fe ions towards the A site at x = 0.1. At x = 0.5, more Fe ions favour the B site. The cation distribution quantitatively obtained from the Mössbauer spectral analysis shows that while 60% of Fe ions occupy the A site in x = 0.1, 40% occupy it in x = 0.5. Surprisingly at x = 0.3, Fe ions are distributed equally among the A and B sites. dc magnetization reveals an increase in TC from 102 K to 200 K and in TS from 26 to 40 K with an increase in Fe concentration, indicating an enhancement in A–B exchange interaction at the expense of B–B. No report has until now demonstrated such an enhancement in TS either in pure or in doped CoCr2O4. Furthermore, frequency-dependent ac susceptibility (χ) data fitted with different phenomenological models such as the Néel–Arrhenius, Vogel–Fulcher and power law confirm a spin-glass and/or cluster-glass behaviour in nanoparticles of CoCr2−xFexO4.

Graphical abstract: Cation distribution dependent magnetic properties in CoCr2−xFexO4 (x = 0.1 to 0.5): EXAFS, Mössbauer and magnetic measurements

Back to tab navigation

Publication details

The article was received on 19 May 2017, accepted on 07 Jul 2017 and first published on 07 Jul 2017


Article type: Paper
DOI: 10.1039/C7DT01831B
Citation: Dalton Trans., 2017,46, 10300-10314
  •   Request permissions

    Cation distribution dependent magnetic properties in CoCr2−xFexO4 (x = 0.1 to 0.5): EXAFS, Mössbauer and magnetic measurements

    D. Kumar, A. Banerjee, A. Mahmoud and C. Rath, Dalton Trans., 2017, 46, 10300
    DOI: 10.1039/C7DT01831B

Search articles by author

Spotlight

Advertisements