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The effect of stress in soft magnetic thin films, in particular, on the in-plane anisotropy, has been studied, based on the analysis of the magnetoelastic energy associated with the stress. The easy-axis directions and the effective anisotropy constants have been identified, as functions of the stress, the magnetostriction coefficients of the material, and the growth texture of the film. The magnetoelastic energy has been combined into an existing micromagnetic model to simulate the magnetization of thin films with various materials, stress states, and growth textures. Simulation results of static magnetic domain structures are in agreement with the theoretical predictions. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Magnetization dynamics during field reversal in thin film recording heads are studied via micromagnetic modeling. It is found that head field reversal under the current field can be characterized by two stages: an initial stage that is mainly governed by the gyromagnetic motion and virtually independent of energy damping, followed by a damping stage that strongly depends on the energy damping constant. Due to the finite energy damping in practical recording heads, the head field amplitude will roll off at high recording frequencies. Simply decreasing the current rise time or increasing current amplitude will not alleviate the situation, but rather worsen it. There exists an optimum current rise time at which the head field rise time is minimized and the roll-off frequency is maximized. [ABSTRACT FROM AUTHOR]

A perpendicular write head with a stitched pole tip and side yoke recessed from the air-bearing surface is proposed and investigated using three-dimensional micromagnetic modeling. The design yields an increase of head field magnitude by 30% over the conventional single pole head. It is found that the optimal flare angle at the bottom of the yoke is 45°, for maximizing the on-track field magnitude and getting the minimum off-track field at the same time. Reducing the throat height significantly increases on-track field, while the off-track field increases as well. Lamination of the pole tip is necessary for producing robust zero remanent field for deep-submicron track widths. Introducing adequate transverse anisotropy in the head will significantly shorten the relaxation time of the magnetic moments after writing with little degradation on write efficiency. [ABSTRACT FROM AUTHOR]

A three-dimensional micromagnetic model has been developed to study single pole write heads with soft magnetic underlayer (SUL) for perpendicular recording at extremely small track widths. The study points out that at any practical ABS-to-SUL spacing, the maximum head field within the recording media at deep submicron track width and pole-tip thickness becomes significantly smaller than the ideal value of 4πM[sub s]. Head field gradient in the medium also degrades with decreasing track width. Maintaining the conventional design, a significantly large remanent head field develops for track width below 100 nm, presenting danger of erasing previously recorded bits. The origin of the large remanent head field is the failure for a pole tip to reach a completely demagnetized state due to the overwhelming ferromagnetic exchange energy at the deep submicron pole-tip dimensions. [ABSTRACT FROM AUTHOR]

A computational study of the head field was presented in a specific head/media configuration, where the intermediate layer (IL) consists of the periodic magnetic columns and Ru columns. It was found that the head field increases with the thicker and wider magnetic columns. Micromagnetic simulation shows that this approach is to achieve a lower effective IL thickness for enhancing the write field by replacing some Ru grains with the columnar magnetic material without reducing the IL thickness. [ABSTRACT FROM AUTHOR]

We present a systematic study of write field asymmetry by using micromagnetic modeling for a perpendicular magnetic recording (PMR) writer structure. Parameters investigated include initial magnetization condition, write current amplitude, write current frequency, and initial write current polarity. It is found that the write current amplitude and frequency (data rate) are the dominant factors that impact the field asymmetry. Lower write current amplitude and higher write current frequency will deteriorate the write field asymmetry, causing recording performance (such as bit error rate) degradation. [ABSTRACT FROM AUTHOR]