Correlation between noise-after-write and magnetization dynamics in thin film heads

A micromagnetic study of the reversal mechanism in permalloy antidot arrays J. Appl. Phys. 111, 053915 (2012); 10.1063/1.3689846Six-fold configurational anisotropy and magnetic reversal in nanoscale Permalloy triangles Effect of the classical ampere field in micromagnetic computations of spin polarized current-driven magnetization processes Lorentz microscopy has been used to study the micromagnetic processes occurring during the reversal of multiscale permalloy elements. The elements, which have similar dimensions to write heads used in magnetic recording, typically have length scales varying from 10 m in the element "core" down to 100 nm in the element "tip." A discussion of the effect of varying the geometry and critical dimensions of the elements on the reversal behavior and switching fields is presented. While the magnetization processes in the core tend to be similar to what is observed in the absence of a tip, the presence of the core strongly influences the tip reversal, even for tips with widths of 100 nm. The results demonstrate clearly the role played by shape anisotropy in complex shaped elements fabricated from an isotropic magnetic film.

Section: Introductionmentioning

confidence: 99%

Micromagnetic reversal behavior of multiscale permalloy elements

Craig

McVitie

Chapman

et al. 2007

Dynamic domain instability and popcorn noise in thin-film heads

Liu

Kryder

1994

The effects of dynamic domain instability on popcorn noise probabilities were studied by correlating the measured popcorn noise probabilities with the instantaneous observations of dynamic domain states of thin-film: heads during and after writing. Heads with large peak popcorn noise probabilities at intermediate values of write current amplitude were observed to exhibit asymmetric domain patterns and occa.sional popping wall motion in the yoke structure during writing. The occurrences of dynamic domain instability were imaged by comparing many instantaneous domain patterns at 10 ,US after a specific write current excitation. Delayed-relaxation Barkhausen wall jumps near the backgap closure were observed occasionally in several noisy heads. Quantitative &orrelation between the probabilities of popcorn noise. and dynamic domain instability was also obtained in a very noisy head. :Dynamic domain instabilities in the yoke are thus responsibIe for the peak popcorn noise probabi1itie.s in thin-film heads.

Dynamic response of domain walls on the air-bearing surface of thin-film heads

Xiao-li

Liu

et al. 1994

The domain configurations on the air-bearing surface (ABS) of inductive thin-film recording heads were studied. It was found that, instead of being a single domain structure, the ABS of a thin-film head usually has multidomains. The direction of the domain walls is neither parallel nor perpendicular to the gap plane. The magnetization was found to be in the plane of the ABS along the track width, with the magnetizations on the two sides of the domain walls either "head-to-head" or '"tail-to-tail." The domain walls are slanted in order to spread the magnetic charges along the wall over a larger region, thereby reducing magnetostatic energy in this configuration. The responses of the domain walls are not all in phase, and they are generally out of phase with the rotational process along the gap edge. The magnetization configuration on the ABS and in the throat and the sloped region were investigated in one. head and correlated with the domain walls on the ABS.