Effects of the substitution of rare-earths R = Y, Er, and Ho on the magnetic properties of Dy 0.7 R 0.3 CrO 3 are reported here in order to probe the nature of magnetism and related exchange interactions in these materials. By fitting the temperature dependence of the magnetic susceptibility to a modified Curie-Weiss law, which includes a correction for the Dzyaloshinskii-Moriya (DM) interaction, the strengths of the symmetric and antisymmetric Cr 3+-Cr 3+ exchange interactions were determined. It was found that the rare-earth substitutions had a slight effect on the strength of the symmetric Cr 3+-Cr 3+ interaction (reflected in the slight changes in the Néel temperatures) while the antisymmetric Cr 3+-Cr 3+ interaction remained unchanged. Isothermal magnetic measurements of the samples at successive temperatures revealed a plateau in the temperature dependent magnetic coercivity data, which was explained by the magnetic properties of the substituted ions. It was found that the Y substitution lead to the reduction of the strength of the magnetization and a larger peak value of magnetic coercivity as compared to that in pure DyCrO 3. The observed increase in coercivity with Er and Ho substitution can be attributed to an increased R 3+-Cr 3+ interaction strength dominated by the DM mechanism.

In this work, a polycrystalline bulk DyCrO 3 sample was prepared by a solution route and the structural and magnetic properties were investigated. The phase purity and ionic valence state of the DyCrO 3 sample were determined by x-ray diffraction/Raman spectroscopy and x-ray photoelectron spectroscopy, respectively. The AC and DC magnetization measurements revealed the onset of antiferromagnetic order at 146 K with an effective moment of 8.88 l B . Isothermal magnetization measurements of this material are presented for the first time, showing a peak in the coercive field at 80 K that is explained by the competition between the paramagnetic Dy 3þ and Cr 3þ sublattices. DyCrO 3 was found to display a large magnetocaloric effect (8.4 J/kg K) and relative cooling power (217 J/kg) at 4 T applied field, which renders DyCrO 3 useful for magnetic refrigeration between 5 K and 30 K. V C 2013 AIP Publishing LLC. [http://dx.

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