Kerr effect imaging of dynamic processes in magnetic recording heads

Kryder, M.H.; Koeppe, P.; Liu, F.H.

doi:10.1109/20.102879

Cited by 31 publications

(6 citation statements)

References 32 publications

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“…the component of magnetization being sensed in the head) was chosen to be transverse to the head symmetry axis. A scanning magneto-optic p h e tometer with 200 MHz bandwidth was used to observe the time-averaged dynamic magnetic response [4] at the sloped region of the pole tip. The small spot size of the incident light (R 0.3 pm) in this imaging system provides a good means to probe the signal from the small and topographically rough sloped region.…”

Section: Methodsmentioning

confidence: 99%

“…Within each head pair, one was annealed with no magnetic field at 23OoC for 4 hours, while the other was not. Two complementary magneto-optic Kerr effect imaging systems [4] were used to study dynamic magnetic phenomena in the yoke structures and the sloped regions of the pole tip of the thin film heads. A wide-field magneto-optic domain observation system with a 10-ns exposure time [4,5] was used to observe the instantaneous magnetization response on the top yoke.…”

Section: Methodsmentioning

confidence: 99%

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

et al. 1992

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Correlation between noise-after-write and magnetization dynamics i n 30-turn electroplated thin film heads has been investigated by utilising two complementary magneto-optic Kerr effect domain imaging systems and a Barkhausen noise tester. It has been found that heads containing spike-like domains near the backgap closure have significantly higher noise-after-write rates than heads with normal closure domain configurations. A longitudinal 180° wall in the direction of flux conduction at the sloped region of the pole tip was observed, however, independent of whether the head had a high or low noise-after-write rate.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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

et al. 1992

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“…The authors go on [73] to investigate nonlinear transition shifts in high-frequency magnetic heads caused by transient flux effects associated with high data rates (as opposed to nonlinear effects caused by areal density). Previous optical time-resolved recording head work also includes [74,75,76,77,78].…”

Section: Magnetic Device Characterization and Nonrepetitive Processesmentioning

confidence: 99%

Stroboscopic Microscopy of Magnetic Dynamics

Freeman

Hiebert

Topics in Applied Physics

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Abstract. The enhanced capabilities of contemporary pulsed light sources have led to the reflourishing, in recent years, of ultrafast imaging of micromagnetic dynamics. Concurrently, interest in the subject has been intensified by other factors, such as the emergence of intrinsic magnetic response times as a potential limitation to the ultimate bandwidth of magnetic data storage and by increasingly powerful computer models of magnetic dynamics which call for experimental comparisons. This review contains a discussion of the experimental details behind ultrafast timeresolved magneto-optic imaging, sandwiched between a brief historical overview and a presentation of some recent results, and accompanied by an outline of some future prospects. Historical OverviewThe ongoing development of ultrafast laser technologies has made stroboscopic imaging of fast dynamics in microscopic structures very convenient. The stroboscopic, or "pump-probe" method as it is traditionally named by the optics community, has been grafted onto many different varieties of microscopy, including electron beam, scanning probe (force and tunneling), and, of course, optical (both conventional and near-field) [1,2,3,4]. Some applications of ultrafast optical microscopy are more fully developed than ultrafast scanning probe microscopies, many of which are still not too far beyond the "proof-of-principle" stage. This is largely because the development time for an ultrafast optical microscope is much shorter than that for combinations of ultrafast lasers with other imaging methods.Magnetic structures in particular have provided a major test bed for developments in ultrafast optical microscopy. The magneto-optic activity of ferromagnetic materials ideally suits them for this kind of experimental analysis. With characteristic relaxation times and oscillation periods ranging into the low picosecond range, and with domain wall widths and spin-wave wavelengths in the nanometer range, spatiotemporal investigation of these materials poses a difficult challenge for any type of microscopy. Ferroelectrics are another class with similar characteristics [5].As is often the case, the territory we explore now and find so fertile turns out to have been well surveyed by our predecessors, using the best tools of

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“…If the wall motion is non-repeatable from cycle to cycle, images obtained using the strobed KMO system will be blurred, distorted or simply not visible. Stroboscopic high energy pulsed (1 ns) laser systems have been used in studies on other materials where the light intensity of each pulse is sufficiently high for capturing real-time images [34].…”

Section: Real-time Domain Observationsmentioning

confidence: 99%