Effect of intergranular interactions on thermal energy barrier distribution in perpendicular media

Abstract

Micromagnetic simulations have been performed to simulate dynamic hysteresis loops in perpendicular media. Thermal energy barrier distributions have been calculated. For a fixed percentage of magnetization switched, a linear variation between the scaled applied field H a(t)/H K and ln(f 0t) 1/2 is found. Without including intergranular magnetostatic interactions, intergranular exchange coupling reduces the thermal energy barrier distribution width, compared to the physical volume distribution width. However, the magnetostatic interactions increase the energy barrier width substantially. The increase is significantly reduced at smaller magnetostatic interactions. For the effective volume of 50% magnetization switched (V 50), the results show V 50= 〈V 2〉 almost independent of intergranular magnetostatic and exchange interactions. © 2002 American Institute of Physics.