Mössbauer Study of Several Ferrimagnetic Spinels

Magnetic and magnetoelastic properties of Cr-substituted cobalt ferrite

“…It can be inferred from the Mössbauer spectroscopy results that the Cr 3+ ions have a stronger B-site preference than the Mn 3+ ions, and are more effective in displacing Co 2+ ions from the B sites to the A sites 10,11 ͑each of which is superexchange linked to 12 next-nearest neighbors at the B sites͒. 5 This means that not only are Fe 3+ ions on B sites being replaced by Cr 3+ ions as a result of compositional substitution but those Fe 3+ ions that remain at B sites are superexchange linked to fewer A-site Fe 3+ ions, as Co 2+ ions are displaced to A sites. Thus the Curie temperature decreases more with Cr substitution than with Mn substitution.…”

“…The Co 2+ ions in cobalt ferrite are generally reported to show a preference for the octahedral ͑B͒ sites, but they do not exclusively reside in the octahedral ͑B͒ sites, and the distribution is reported to depend on thermal treatment. 5 The magnetic and magnetoelastic properties of ferrites are dependent on exchange interactions, and the latter depend on how the cations are distributed among the two sublattices. [6][7][8] Tailoring the chemical composition of cobalt ferrites allows control of the physical properties, including the temperature dependence of magnetic properties and magnetomechanical hysteresis.…”

Controlling the electronic structure of Co1−xFe2+xOMoyer1, Vaz2, Negusse3 et al. 2011Phys. Rev. B8917740View full textAdd to dashboardCite

“…The crystal structure of cobalt ferrite is no longer fully inverse spinel; the majority of Co 2+ cations occupy octahedral sites, although a small fraction (2 -24%, depending strongly on the thermal history of the sample) 37 are located on the tetrahedral sites. 37,38 The Fe 3+ cations are now distributed unevenly between the octahedral and tetrahedral sites ( Fig. 1(c)).…”

Effect of substrate temperature on magnetic properties of MnFe2O4 thin films

“…11 However, the strength of exchange interaction for Mn 2+ (A)-Fe 3+ (B) is smaller than that of Fe 3+ (A)-Fe 3+ (B). 5,6,12,13 Hence any change in inversion affects the exchange constant but not the net magnetic moment. 6,11,12 In this paper, we report the magnetic properties of MnFe 2 O 4 thin films pulsed laser deposited (PLD) at various substrate temperatures (T S ).…”