Investigation of Ga substitution in cobalt ferrite (CoGaxFe2-xO4) using Mossbauer spectroscopy

Krieble, K., Devlin, M., Lee, S. J., Aldini, S. and Snyder, John Evan 2008. Investigation of Ga substitution in cobalt ferrite (CoGaxFe2-xO4) using Mossbauer spectroscopy. Journal of Applied Physics 103 (7) , 07E508. 10.1063/1.2834721

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Abstract

Ga-substituted cobalt ferrite oxides show promise as high magnetostriction, high sensitivity magnetoelastic materials for sensor and actuator applications, but their atomic-level behavior is not yet well understood. In this study, the magnetic environments of the Fe atoms in Ga-substituted cobalt ferrite have been investigated using Mossbauer spectroscopy. A series of five powder samples with CoGaxFe2−xO4 compositions (x = 0.0–0.8) was investigated using transmission geometry. Results show two distinct six-line hyperfine patterns, which are identified as Fe in A (tetrahedral) and B (octahedral) spinel sites. Increasing Ga concentration is seen to decrease the hyperfine field strength for both A and B sites, as well as increasing the width of those distributions, consistent with the nonmagnetic nature of Ga3+ ions. Effects are more pronounced for the B sites than the A sites. Results for Ga substitution show more pronounced effects than for previous studies with Cr3+ or Mn3+ substitution: the hyperfine fields decrease and distribution widths increase at greater rates, and the differences between A and B site behavior are more pronounced. Results indicate that at least for the lower Ga concentrations, the Ga3+ ions substitute predominantly into the A sites, in contrast to Cr3+ and Mn3+ which substitute into the B sites. This interpretation is supported by measurements of magnetization at low temperatures.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Engineering
Uncontrolled Keywords:	chemical exchanges, cobalt compounds, ferrites, gallium compounds, hyperfine interactions, magnetisation, magnetostriction, Mossbauer effect
Publisher:	American Institute of Physics
ISSN:	0021-8979
Last Modified:	16 May 2023 22:51
URI:	https://orca.cardiff.ac.uk/id/eprint/5439

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