Magnetic Phase Diagram of Ca1− xMn xO.

Alternating current susceptibility and direct current magnetization have been studied for polycrystalline Ca_{1− x}Mn _xO. 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. [ABSTRACT FROM AUTHOR]