Micromagnetic study on microwave-assisted magnetic recording in perpendicular medium with intergrain exchange coupling

作者：Nozaki Yukio^*; Kato Ayumu; Noda Kenji; Kanai Yasushi; Tanaka Terumitsu; Matsuyama Kimihide

来源：Journal of Applied Physics, 2011, 109(12): 123912.

DOI：10.1063/1.3596805

The influence of intergrain exchange coupling on the properties of microwave-assisted magnetization reversal has been investigated. The results of micromagnetic simulation suggest that the microwave frequency realizing the magnetization reversal is increased as the exchange stiffness constant among the magnetic grains becomes larger than 1 x 10(-7) erg/cm if an inhomogeneous magnetization reversal occurred. The numerically expected increase in the microwave frequency was observed experimentally in perpendicularly magnetized Co/Pd multilayer with an exchange stiffness constant of similar to 1 x 10(-6) erg/cm. The simulations of signal recording and reproducing processes in a granular medium with assistance of a microwave field also suggest that an adequate intergrain exchange coupling is required to inhibit the nucleation of small island domains that will suppress the amplitude of the signal-noise ratio of the readback signal.

• 出版日期2011-6-15