Quick search Find article
Quick search
Find article

Cation occupancies in Mg, Co, Ni, Zn, Al ferrite spinels: a multi-element EXAFS study

C M B Henderson1,2, J M Charnock1,2 and D A Plant2

Show affiliations


The distribution of cations between tetrahedral (A) sites and octahedral (B) sites in ferrite spinels has been studied using K-edge x-ray absorption spectroscopy. The samples include natural and synthetic end-member magnetites (Fe3O4), a natural Mn- and Zn-rich magnetite (franklinite) and synthetic binary, ternary and quaternary ferrites of stoichiometry M2+M23+O4, where M2+ = Mg, Co, Ni, Zn and M3+ = Fe, Al. XAS data were obtained for all metals. Complete, unfiltered, EXAFS spectra were refined to determine the percentage distribution of each element over the A and B sites and these data were combined with microprobe analyses to quantify the tetrahedral occupancy for each element in each sample. Measured site occupancies and an internally consistent set of (M–O)A and (M–O)B bond lengths were used to calculate unit-cell parameters, which show excellent agreement with measured values, pointing to the reliability of the measured occupancy factors. The average occupancies determined for the tetrahedral sites in ferrites are (atoms per formula unit) Mg 0.44, Co 0.24, Ni 0.11, Zn 0.76, Al 0.11 and Fe3+ 0.92–0.19. The wide range found for Fe3+ is consistent with it playing a relatively passive role by making good any A-site deficit left by the other competing cations.


PACS

78.70.Dm X-ray absorption spectra

61.50.Lt Crystal binding; cohesive energy

61.50.Nw Crystal stoichiometry

75.50.Gg Ferrimagnetics

61.05.cj X-ray absorption spectroscopy: EXAFS, NEXAFS, XANES, etc.

Subjects

Condensed matter: electrical, magnetic and optical

Condensed matter: structural, mechanical & thermal

Dates

Issue 7 (21 February 2007)

Received 18 December 2006, in final form 8 January 2007

Published 2 February 2007



  1. Cation occupancies in Mg, Co, Ni, Zn, Al ferrite spinels: a multi-element EXAFS study

    C M B Henderson et al 2007 J. Phys.: Condens. Matter 19 076214

  2. Dynamics of molecular self-ordering in tetraphenyl porphyrin monolayers on metallic substrates

    Jens Brede et al 2009 Nanotechnology 20 275602

  3. Carbon nanotube field-effect transistor with a carbon nanotube gate electrode

    Ji-Yong Park 2007 Nanotechnology 18 095202

  4. Gravitational-wave sources

    B F Schutz 1996 Class. Quantum Grav. 13 A219

  5. Lunar Occultations of Young Stars in Southern Taurus

    M. Simon et al. 1999 The Astronomical Journal 117 1594

  6. 1/f noise in computer network traffic

    I Csabai 1994 J. Phys. A: Math. Gen. 27 L417

  7. Quasi-stationary perturbations of the KdV soliton

    Russell L Herman 2004 J. Phys. A: Math. Gen. 37 4753

  8. Modelling binary black-hole coalescence

    John Baker 2003 Class. Quantum Grav. 20 S201

  9. Gravitational waves from extreme mass ratio inspirals: challenges in mapping the spacetime of massive, compact objects

    Scott A Hughes 2001 Class. Quantum Grav. 18 4067

  10. Cosmology with coalescing massive black holes

    Scott A Hughes and Daniel E Holz 2003 Class. Quantum Grav. 20 S65

Related review articles

What's this?
View review articles related to this research to gain an insight into the key trends in this subject area. Related review articles are selected based on PACS/MSC codes, and are no more than three years old.

  1. Extended x-ray absorption fine structure studies of the atomic structure of nanoparticles in different metallic matrices

View by subject




Export








Please login to access our web services, or create an account if you don't yet have one.

You must have cookies enabled in your web browser to be able to login.

Username
Password

Forgotten your password? Get a new one here.