Magnetic behaviour of the antiferromagnet

The magnetic behaviour of the antiferromagnet was investigated through heat capacity, magnetic susceptibility and magnetization measurements. The broad magnetic susceptibility curve (peaked at 15 K) presents an inflection typical of two-dimensional systems. This inflection is observed near 10 K, the temperature at which early reported Mössbauer measurements indicate the onset of magnetic order. The heat capacity measurements have shown a clear transition at 8.7 K, where Mössbauer measurements show complete ordering. Magnetization curves, for temperatures between 1.4 K and 5 K, display a noticeable change in slope, suggesting a spin-flop transition induced by a field higher than 10 T. It is argued that this transition, which disappears for , is evidence of two-dimensional behaviour.