Magnetic properties of the ferrimagnetic cobaltite CaBaCo4O7

Abstract

The magnetic properties of the ferrimagnetic cobaltite CaBaCo${}_4$O${}_7$ are systematically investigated. We find that the susceptibility exhibits a downward deviation below $\sim$ 360 K, suggesting the occurrence of short range magnetic correlations at temperature well above $T_C$. The effective moment is determined to be 4.5 $\hat{I}{¼}_B$/f.u, which is consistent with that expected for the Co${}^{2+}$/Co${}^{3+}$ high spin species. Using a criterion given by Banerjee [Phys. Lett. \textbf{12}, 16 (1964)], we demonstrate that the paramagnetic to ferrimagnetic transition in CaBaCo${}_4$O${}_7$ has a first order character.

9 pages, 4 figures. To be published in Solid State Communications