Temperature dependence of magnetic hysteresis scaling for cubic Fe3O4 nanoparticles

We have examined magnetic hysteresis scaling of minor loops for cubic Fe3O4 nanoparticles with particle diameter of 265 nm in order to seek a possible application of the method for characterization of magnetic nanoparticles. While the conventional Steinmetz law fails, a power-law scaling with an exponent of 1.3±0.1 was found to universally hold true between the remanence and hysteresis loss of minor loops below and above the Verwey temperature of ∼ 100 K. A minor-loop coefficient obtained from the power law exhibits a sudden increase with an onset of Verwey transition, followed by a steep increase with decreasing temperature. The increase of the coefficient at Verwey transition is by 390%, being much higher than 260% for major-loop coercivity. There observations demonstrate that a magnetic hysteresis scaling using symmetrical minor loops can be a possible technique for characterizing magnetic nanoparticles due to its sensitivity to materials intrinsic properties and low measurement fields below 1 kOe.