Evaluation of Relaxational and Hysteretic Heat Losses in Concentrated Magnetic Fluid under Influence of Alternating Magnetic Field

This article describes the magnetic and hyperthermic investigation of a concentrated magnetic fluid on the basis of a transformer mineral oil with magnetite particles. The structure of a ferrofluid and general magnetic parameters of a medium were determined from vibrating sample magnetometer measurements. The hyperthermic experiments were carried out at a frequency f = 1500 kHz for various magnetic field amplitudes. The analysis of calorimetric results allowed an estimate of the contribution of relaxational and hysteresis loss mechanisms in total energy losses in the hyperthermic effect under the influence of an alternating magnetic field. Additional calorimetric measurements were also performed (at H C = 1500 A · m−1) versus frequency in the range from 50 kHz to 2 MHz which indicated that for f o = 653 kHz the heating process is the most effective.