The spin-lattice relaxation time of

The magnetization configurations within the pole tip of the single-pole-type head have been examined through a micromagnetic computer simulation based on the Landau–Lifshitz–Gilbert equation. The aspect ratio, including the effect of the exchange length (Lex), was defined as the ratio of the throat height (Th) to the write-track width (Tww) and the thickness (Tp), which is given (Th×Lex)/(Tww×Tp). It was found that the magnetization configuration and the perpendicular component of remanent head field (Hr) are strongly dominated by this aspect ratio at any value of Tww. It was also found that there is a characteristic aspect ratio at which Hr starts to decrease. These results show that decreasing the aspect ratio is an effective way to reduce the intensity of the remanent head field.

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The effects of longitudinal bias field, used for domain control on the magnetization distribution in a magnetoresistive (MR) film, have been investigated by computer simulation. The longitudinal bias field was generated by an exchange-coupled antiferromagnetic or permanent magnetic film formed on the MR film outside the sensing region. It was assumed that the magnetization in the part of the MR film on which the bias-generating films were formed was fixed along the easy axis. The spatial sensitivity of the MR film along the track width was evaluated by calculating the dependence of the resistance change on the position of a narrow track recording medium. It was found that the resistance change in the MR film with the anti-ferromagnetic film was roughly twice as large as the change in the film with the permanent magnetic film. The asymmetric sensitivity profile with respect to reflection about the track width mid-plane was also obtained. The asymmetry in the track sensitivity profile was found to be caused by three factors: asymmetric magnetization distribution about the track width mid-plane due to the transverse bias field, the difference in angular changes in the magnetization direction in the left and right regions facing the recording medium, and anisotropic flux propagation in the MR film.