Magnetic phase diagram of Ca_1-xMn_xO

Abstract

Alternating current susceptibility and direct current magnetization have been studied for polycrystalline Ca${}_{1-x}$Mn${}_x$O. On increasing the Mn content, magnetic ordering changes from spin-glass behavior for $0.25⩽x⩽0.4$ to antiferromagnetic order. The paramagnetic/antiferromagnetic transition is of second order for $0.5⩽x⩽0.65$ and of first order for $x⩾0.7$. For low Mn concentrations, the high-temperature alternating current susceptibility can be described by a diluted Heisenberg magnet model developed for diluted magnetic semiconductors.

5 pages, 5 figures, RevTeX, To be published in J. Supercond.: Incorp. Novel Materials