Magnetic resonance of field-frozen and zero-field-frozen magnetic fluids

In this study magnetic resonance was used to investigate magnetic fluid samples frozen under zero and non-zero (15 kG) external fields. The magnetite-based sample containing 2x1017 particle/cm3 was investigated from 100 to 400 K. Analysis of the temperature dependence of the resonance field revealed bigger magnetic structures in the frozen state than in the liquid phase. Also, differences in the mesoscopic organization in the frozen state may explain the data obtained from samples frozen under zero and non-zero fields