Magnetic and magnetoelastic properties of Cr-substituted cobalt ferrite

We have investigated the magnetic and magnetoelastic properties of a series of Cr-substituted cobalt ferrite CoCrxFe2−xO4 (x=0.0–0.79) samples. Substitution of Cr for some of the Fe in cobalt ferrite reduced the Curie temperature, and the effect is more pronounced than that observed in Mn-substituted cobalt ferrite samples. Cr substitution also caused the maximum magnetostriction to decrease at a greater rate than substitution of the same amount of Mn. The maximum of the strain derivative, dλ∕dH, was reached for x=0.38. The behavior of the Curie temperature of Cr-substituted and Mn-substituted cobalt ferrites has been analyzed using the Néel molecular field model and compared with recent Mössbauer spectroscopy results.