Introduction to Micromagnetic Recording Physics

Ek, J. van; Plumer, M. L.

doi:10.1007/978-3-642-56657-8_1

Cited by 5 publications

(5 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As an outlook, it is still early to predict whether such alloptical ultrafast switching of the magnetization could become useful in, for example, magnetic recording devices. The last years have seen a considerable slow-down of the annual growth in the magnetic recording industry, forcing the leading companies to look for novel approaches [160], such as heatassisted magnetic recording [161] and bit-patterned media [162]. In the former, a laser is introduced in the write-head, to assist the magnetic switching of high-anisotropy media.…”

Section: Discussionmentioning

confidence: 99%

Laser-induced magnetization dynamics and reversal in ferrimagnetic alloys

Kirilyuk

Kimel²,

Rasing³

2013

Rep. Prog. Phys.

236

179

View full text Add to dashboard Cite

This review discusses the recent studies of magnetization dynamics and the role of angular momentum in thin films of ferrimagnetic rare-earth-transition metal (RE-TM) alloys, e.g. GdFeCo, where both magnetization and angular momenta are temperature dependent. It has been experimentally demonstrated that the magnetization can be manipulated and even reversed by a single 40 fs laser pulse, without any applied magnetic field. This switching is found to follow a novel reversal pathway, that is shown however to depend crucially on the net angular momentum, reflecting the balance of the two opposite sublattices. In particular, optical excitation of ferrimagnetic GdFeCo on a time scale pertinent to the characteristic time of the exchange interaction between the RE and TM spins, i.e. on the time scale of tens of femtoseconds, pushes the spin dynamics into a yet unexplored regime, where the two exchange-coupled magnetic sublattices demonstrate substantially different dynamics. As a result, the reversal of spins appears to proceed via a novel transient state characterized by a ferromagnetic alignment of the Gd and Fe magnetic moments, despite their ground-state antiferromagnetic coupling.Thus, optical manipulation of magnetic order by femtosecond laser pulses has developed into an exciting and still expanding research field that keeps being fueled by a continuous stream of new and sometimes counterintuitive results. Considering the progress in the development of plasmonic antennas and compact ultrafast lasers, optical control of magnetic order may also potentially revolutionize data storage and information processing technologies.

show abstract

Section: Discussionmentioning

confidence: 99%

Laser-induced magnetization dynamics and reversal in ferrimagnetic alloys

Kirilyuk

Kimel²,

Rasing³

2013

Rep. Prog. Phys.

236

179

View full text Add to dashboard Cite

show abstract

“…There is little impact (5%) in reducing the moment of the SUL from 2.0 to 1.0 T. Changing the top pole material from 2.4 to 1.6 T, however, has a significant impact. The micromagnetic recording model (MRM) [13] was used to further examine the effects of changing the SUL and top pole materials. A FEM calculated head field was applied to a LLG model of granular media to record transitions.…”

Section: Modeling Effects Of the Soft Underlayer On The Write Fieldmentioning

confidence: 99%

“…Faster switching occurs if there is a significant component of the head field in a direction perpendicular to the medium magnetization [14]. For longitudinal recording with a gapped head, the write field impinges the medium at about a 45 angle [13]. Fig.…”

Section: Modeling Effects Of the Soft Underlayer On The Write Fieldmentioning

confidence: 99%

Measurements and modeling of soft underlayer materials for perpendicular magnetic recording

et al. 2002

View full text Add to dashboard Cite

Measurements and modeling of soft magnetic underlayer (SUL) materials for perpendicular magnetic recording application are carried out. The process dependent magnetic properties of FeCoB, CoZrNb, and FeAlN SUL materials on glass and aluminum disk substrates are studied and correlated with spin-stand noise performance. The SUL-induced dc noise amplitude approaches the electronic noise floor for certain material combinations, e.g., FeCoB or CoZrNb on glass, when care is taken to relieve stress-induced perpendicular anisotropy by thermal annealing. Landau-Lifshitz-Gilbert micromagnetics, finite-element method calculations, and a micromagnetic recording model show that write field amplitude, write field gradient, and readback waveform are only slightly impacted by SUL moment in the 1-2 T range. Much more important are the head-to-SUL distance and the write head saturation moment. These results suggest that extremely high SUL moment may not be necessary, which can be leveraged to meet other key practical requirements such as corrosion resistance and manufacturability.Index Terms-Finite-element method, Landau-Lifshitz-Gilbert, noise, perpendicular magnetic recording, soft magnetic underlayer, stripe domains. ).M. Plumer and J. van Ek are with Seagate Technology, Bloomington, MN 55435 USA.

show abstract

“…Several studies on possible limitations on the data rate have been performed in the past years. They include works on the switching speed of the media [4], [5], fast writers [6], [7], as well as on the gyromagnetic effects and how they affect the speed at which the data can be retrieved [8]. Little attention has been paid to the effects of parasitic capacitance coupling through various head components.…”

Section: Introductionmentioning

confidence: 99%

Lumped-element RC model for high-data-rate thin-film heads

et al. 2003

View full text Add to dashboard Cite

We have developed a lumped-element model for a thin-film giant magnetoresistive head with an inductive writer and used it to study the effect on the data rate capability. Our work shows that the reader can be approximated well by a resistor ( e ) and a capacitor ( e ) in parallel. The paper discusses the relative importance of different contributors to e and addresses the effect of e on the spectrum of the read-back signal and the electrical reader pulsewidth (PW50) in detail. The model predictions and spin-stand data agree reasonably well. The paper also reports on our study of the amount of writer-to-reader coupling in the transducer. Our work points out the importance of minimizing the parasitic capacitance between elements in the writer and reader and avoiding direct coupling between the writer and reader leads.Index Terms-High data rate, magnetic disk storage, magnetic heads, writer-to-reader coupling.

show abstract

Introduction to Micromagnetic Recording Physics

Cited by 5 publications

References 20 publications

Laser-induced magnetization dynamics and reversal in ferrimagnetic alloys

Laser-induced magnetization dynamics and reversal in ferrimagnetic alloys

Measurements and modeling of soft underlayer materials for perpendicular magnetic recording

Lumped-element RC model for high-data-rate thin-film heads

Contact Info

Product

Resources

About