Hysteretic behavior of magnetic particles with dipole interaction

Energy barrier height and coercivity variation of a pair of interacting particles has been studied as a function of the bonding angle beta for 0 degrees less than or equal to beta less than or equal to pi/2 and applied field using the fixed step Monte Carlo simulation approach supplemented by the perturbation method. Coercivity H-c (beta) of the system has local maxima at beta=0 and p/2, and a global minimum at beta similar or equal to 65 degrees, and remains depressed compared to the noninteracting case for beta less than or equal to 30 degrees at any temperature. The barrier height behaves similarly. Due to the random nature of distribution dipole interaction, on average, leads naturally to a reduction in coercivity and energy barrier height in comparison with the noninteracting case. (C) 1999 American Institute of Physics. [S0021-8979(99)67308-X].