Magnetic properties of quasi two-dimensional ferric stearate

Results are given of measurements of magnetic susceptibility, electron spin resonance, and Mössbauer effect of ferric stearate. The stearates have long chain hydrocarbons separating by about 50 Å the planes of metal ions. Thus they are excellent examples of quasi two-dimensional magnetic structures. An interesting sample seems to contain some hydroxy-ferric stearate. In this sample we observed that at high temperatures (295 K≥T≥60 K) the magnetization scaled as H/T, as for superparamagnets. Below 60 K there were deviations from this scaling, shifts in electron spin resonance fields, and splittings of the Mössbauer spectrum, indicating a transition to a state of time-independent magnetic order.