Very-low temperature magnetic ordering and dimensionality of the square planar system cobalt(II) phenoxyacetate

The magnetic behaviour of the layered compound [Co(O2C(CH2)OC6H5)2(H2O)2]n (1) has been fully analysed, in the temperature range 150 mK to 300 K. The compound exhibits below 10 K a ferromagnetic-like behaviour and a long-range order at TC=0.57K. The magnetic dimensionality has been analysed by using scaling approach. The high temperature behaviour is well described by an exponential law while in the vicinity of TC a power law variation is characteristic of a 2D to 3D crossover. The critical exponent γ=1.26 deduced by fitting the experimental data above TC agrees well with that expected for an Ising system.