Magnetic Tape Recording Research Articles

Where Tape and Hard-Disk Technology Meet: The HDD Head–Tape Interface

In this paper, we study the mechanical interface between a hard-disk drive (HDD) head and magnetic recording tape to enable the use of HDD heads to investigate future tape operating points. Tape surface height measurements were obtained using an interferometer microscope for varying wrap angle configurations, tape velocities, and tape tensions. Simultaneously, the readback signal from the read element of the HDD head was captured to study the quality of the contact between the tape and the head. The signal-to-noise ratio (SNR) and bit-error rate (BER) performance of pseudorandom bit sequence (PRBS) data readback experiments are presented. An analytical model is described for estimating the magnetic spacing from the PRBS readback spectrum. In contrast to current commercial tape heads, the HDD head surface has a pronounced topography containing cavities. When tape passes in close proximity, subambient pressures are formed inside these cavities and the resulting pressure differences force the tape toward the head and deform the tape into remarkable shapes. For the topography of the HDD head used, the shape of tape is predominantly determined by the leading and trailing wrap angles. Readback was obtained only in the backward direction (i.e., opposite to the direction of operation in an HDD), with positive leading but negative trailing wrap angles. Better readback is obtained for shallow wrap angles, lower tape velocity, and higher tape tension. Good readback is obtained for leading and trailing wrap angles ~0.3° and -0.2°, respectively. Fits of the analytical model to the spectrum of the readback signal of PRBS data lead to a magnetic spacing estimate of ~30 nm. At 600 kb/in linear density, we measured 11 dB SNR and 7 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-3</sup> BER for PRBS data on perpendicularly oriented particulate barium-ferrite tape.

Watching harmonics beat

Suppose you record a song on magnetic tape and duplicate your recording. You then simultaneously play back both tapes. To the rim of one of the tape reels, also known as the reel's flange, you keep applying gentle pressure and then releasing that pressure so that your reel alternates between slightly lagging the other and then catching up with it. The resulting small pitch differences between the two tapes give rise to an intriguing and pleasant sound often described as swirling or jet-like. A Wikipedia article1 lists dozens of popular songs that incorporate this “flanging” effect. Well represented are songs by the Beatles and Jimi Hendrix as well as by artists from recent decades. But perhaps the most important is an obscure 1945 recording by guitarist and musical inventor Les Paul, who is recognized as the discoverer of flanging.

Tunnel Valve Sensors in Contact Recording

Results of experiments in which hard-disk drive (HDD) tunnel valve (TV) sensors were run in continuous contact with magnetic recording tape are presented. In one mode, suspended HDD sliders were run against tape backed by a supporting air film in a novel configuration. In another, tape was run in an air-skiving mode over HDD rowbars mounted on support beams, similar to the way tape wraps a conventional tape head. The data indicate that HDD TV sensors can successfully operate in continuous contact with running tape media. Measurements show that roughness of older generation metal particle tape limits the signal-to-noise ratio achievable using existing narrow HDD TV sensors. However, TV sensors optimized for running on smoother barium ferrite tape are now a viable candidate for future high areal density tape recording platforms.

Effect of doubly layered Ru intermediate layers in perpendicular magnetic recording tape media

Si/NiFe bilayer structures are very effective to obtain c-axis orientation in both a Ru intermediate layer and a CoPtCr-SiO2 recording layer when they successively deposited on the Si/NiFe bilayer. Doubly layered Ru which consists of two Ru layers prepared at low and high sputtering gas pressures promoted c-axis orientation and well-isolated grains of the CoPtCr even when the Ru intermediate layer was very thin. Doubly layered Ru intermediate layers deposited on Si/NiFe seed layers attained suitable c-axis orientation and well-isolated grains of the CoPtCr recording layer, even though the Ru double-layer was as thin as 5 nm.

Preparation and characterization of 6-mercaptopurine-coated magnetite nanoparticles as a drug delivery system.

BackgroundIron oxide nanoparticles are of considerable interest because of their use in magnetic recording tape, ferrofluid, magnetic resonance imaging, drug delivery, and treatment of cancer. The specific morphology of nanoparticles confers an ability to load, carry, and release different types of drugs.Methods and resultsWe synthesized superparamagnetic nanoparticles containing pure iron oxide with a cubic inverse spinal structure. Fourier transform infrared spectra confirmed that these Fe3O4 nanoparticles could be successfully coated with active drug, and thermogravimetric and differential thermogravimetric analyses showed that the thermal stability of iron oxide nanoparticles coated with chitosan and 6-mercaptopurine (FCMP) was markedly enhanced. The synthesized Fe3O4 nanoparticles and the FCMP nanocomposite were generally spherical, with an average diameter of 9 nm and 19 nm, respectively. The release of 6-mercaptopurine from the FCMP nanocomposite was found to be sustained and governed by pseudo-second order kinetics. In order to improve drug loading and release behavior, we prepared a novel nanocomposite (FCMP-D), ie, Fe3O4 nanoparticles containing the same amounts of chitosan and 6-mercaptopurine but using a different solvent for the drug. The results for FCMP-D did not demonstrate “burst release” and the maximum percentage release of 6-mercaptopurine from the FCMP-D nanocomposite reached about 97.7% and 55.4% within approximately 2,500 and 6,300 minutes when exposed to pH 4.8 and pH 7.4 solutions, respectively. By MTT assay, the FCMP nanocomposite was shown not to be toxic to a normal mouse fibroblast cell line.ConclusionIron oxide coated with chitosan containing 6-mercaptopurine prepared using a coprecipitation method has the potential to be used as a controlled-release formulation. These nanoparticles may serve as an alternative drug delivery system for the treatment of cancer, with the added advantage of sparing healthy surrounding cells and tissue.

Side-Reading Effects in High-Track-Density Tape Recording

Aggressive track-density scaling in linear magnetic tape recording has been identified as a key means of sustaining capacity scaling. As the reader width decreases, the relative signal contribution of the written track region outside the lateral extent of the reader increases. We model, analyze and quantify side-reading effects of shielded magneto-resistive read heads reading narrow tracks on perpendicular-oriented tape media. We compare results from extended analytical models with experimental data. An understanding of these effects will be important in designing track misregistration budgets and SNR margins for future operating points of parallel-channel tape recording systems.

Reducing media noise of perpendicular magnetic recording tape for over-50 TB class data cartridge

To reduce medium noise inherent in a perpendicular magnetic recording tape, which is deposited by facing targets sputtering, we have examined an epitaxial double-layered structure consisting of a soft magnetic underlayer (SUL), bcc-FeCoB/fcc-NiFe/Si/bcc-FeCoB, on a 4.5 μm para-aromatic polyamide (aramid) film. An epitaxial soft magnetic bilayer reduces broadband noise by 5.6 dB at 337 kilo fluxchanges per inch (kfci) compared to a single SUL medium (Tape S). This is due to the reduction in the low-frequency noise, which originates from the domain walls of the SUL. Improvement of the crystal orientation of the magnetic layer hcp-CoPtCr–SiO2 and the intermediate layer hcp-Ru by inserting a fcc-NiFe spacer in laminated SULs extends the roll-off curve toward high linear density. When each SUL layer of the bilayer was made thinner, from 25 nm (Tape D2) to 10 nm (Tape D1), the medium noise decreased, improving the signal-to-noise ratio by 8.6 dB at 337 kfci compared to Tape S. In a high resolution playback test of Tape D1, an areal density of 45.0 gigabits per square inch (Gb/in.2) was confirmed. Achieved areal density means the capability of an over-50 terabyte (TB) capacity for a typical linear-formatted data cartridge.

Effect of laminated crystalline FeCoB soft magnetic underlayer for perpendicular magnetic recording tape media

A crystalline FeCoB soft magnetic underlayer (SUL) improves c-axis orientations of the Ru intermediate layer (IML) and the CoPtCr-SiO2 recording layer (RL). (001) orientations of Ru IML and CoPtCr RL are attained by (110) oriented texture of FeCoB SUL. Since good c-axis orientation in CoPtCr-SiO2 RL as well as domain control in the FeCoB SUL is required for high recording density, a laminated FeCoB SUL is prepared as an underlayer of the bilayered Ru/CoPtCr–SiO2 films. A laminated FeCoB SUL results in better (001) orientation in both CoPtCr-SiO2 RL and Ru IML than the single layered FeCoB SUL. This leads to the reduction of media noise in the high recording frequency region. Recording medium layers composed of a laminated FeCoB SUL and bilayered Ru/CoPtCr-SiO2 films deposited on a 4.5-μm-thick Aramid tape show better (001) orientations of Ru and CoPtCr. Media noise of the tape medium with the laminated SUL is lower than that with the single layered FeCoB SUL.

Fragments of Time and Memory

This essay looks at the emergence and development, through technology, of the modern auditory world and asks what its existence in the evolving matrices of time, space and the human body can offer to our understanding of matter and material culture today. The first part explores the materialisation of time in phonographic sound as an instance of the fragmentation of modern life, and how this displaced the temporal experience of the premodern world. The second part looks at the impact of magnetic tape recording – its materiality and malleability – which permitted sound artists to produce multitemporal audio collages that advanced the modern soundscape into the realm of Benjamin's ‘dialectical images’. The essay concludes with a consideration of how the material culture of sound ends in the human body – its final materialism – just as the old sound objects of analogue technology appear to be dematerialised.

Microwave Complex Permeability and Permittivity Measurements of Commercially Available Nano-Ferrites

The dielectric permittivity and magnetic permeability of nano-sized magnetic powders are studied for a wide microwave frequency range from 2 to 40 GHz. These powders are studied for their potential application as soft microwave absorbers in wireless systems as well as for use in the manufacture of small magnetic recording tape, transformers and circulators. A newly developed and precise transmission-reflection based waveguide technique has been used to carry out measurements across the eight frequency bands. These materials have been accurately characterized for the first time across this frequency range. In this paper, we present equations for simultaneous calculation of permittivity and permeability across a wide frequency band using the vector network analyzer. To account for variable sample thickness in the in-waveguide measurements, the algorithm for transmission and reflection calculations has been modified. The results show that the dielectric permittivity depends on the particle size and density of the sample used for measurement.

Fabrication of perpendicular magnetic recording tape media with a data capacity of over-50TB using Si/NiFe/FeCoB soft magnetic underlayers

C-axis orientations of Ru intermediate layer (IML) and CoPtCr-SiO2 recording layer (RL) are attained by using crystalline FeCoB soft magnetic underlayer (SUL). Better (110) orientation of FeCo improves not only (001) orientation of Ru IML but also that of CoPtCr RL. This leads better perpendicular magnetic anisotropy in the RL suitable for perpendicular magnetic recording media. In order to control the (110) orientation in FeCoB layer, various seed layers are prepared beneath the FeCoB layers. Ru and Si/NiFe seed layers gives FeCoB layer a large in-plane magnetic anisotropy that is effective to suppress spike noise from SUL. The laminated FeCoB SUL causes more improvement of Ru (001) texure and leads to better perpendicular magnetic anisotropy of RL. Ru/CoPtCr-SiO2 bilayer deposited on laminated FeCoB SUL on Aramid tape substrate has good perpendicular magnetic properties and reduces the noise from SUL. PACS: Type pacs here, separated by semicolons;

Playback performance of perpendicular magnetic recording tape media for over-50-TB cartridge by facing targets sputtering method

Perpendicular magnetic recording tape medium with laminated soft magnetic underlayers was successively formed on a 4.5 μm thin plastic film by the facing targets sputtering method at room temperature. The tape medium showed extremely high SNR values with sharp transitions in playback tests by a drum tester, compared to a linear format commercial tape medium. An areal density of 45.0 Gb/in. 2 of perpendicular tape medium was confirmed by a high-resolution contact tester. These results suggest that the perpendicular recording tape medium by the facing targets sputtering method is a promising candidate for a tape cartridge of over 50-TB.

First-order reversal curves of magnetic recording tapes

The interaction and its variation between magnetic grains in two kinds of magnetic recording tapes are investigated by first-order reversal curves (FORC) and the δM method. The composition and microstructure of the samples are characterised by x-ray diffraction and scanning electron microscope. The FORC diagram can provide more accurate information of the interaction and its variation, but the δM curves cannot. The positive interaction field and the large variation of the interaction field have opposite effects on the δM curve.

Structure Analysis of Magnetic Nano-particles (Magnetic Recording Tape Materials) by Means of Neutron Diffractometry

Structure Analysis of Magnetic Nano-particles (Magnetic Recording Tape Materials) by Means of Neutron Diffractometry

Effect of Tape Longitudinal Dynamics on Timing Recovery and Channel Performance

The recording performance is compared for two barium ferrite magnetic recording tapes which differ by a factor of two in friction, but are otherwise very similar. The error rate of the tapes is similar at a tape speed of 4 m/s, but as the read or write speed decreases to 1.16 m/s, the error rate of the smoother, higher friction tape increases by a factor of 100. This effect arises from velocity variations in the tape, which prevent accurate timing recovery and uncertainty in the phase of the recorded waveform. The velocity variation is measured by recording a periodic waveform. Its power spectrum demonstrates the effect of the compressional sound wave resonating between rollers on either side of the recording head.

A Portable Electrocardiograph with a Magnetic Tape Recording System for the Horse during Exercise

A Portable Electrocardiograph with a Magnetic Tape Recording System for the Horse during Exercise

Small-angle polarized neutron scattering study of spherical Fe16N2 nano-particles for magnetic recording tape

We have performed small-angle polarized neutron scattering experiments of spherical Fe16N2 nano-particles, which are potential candidate materials for high density magnetic recording tape. The results were analyzed based on a core-shell model, and we evaluated the magnetic structure of the particles. The correlation between the magnetic structure and magnetic stability of the particles were discussed in terms of high density recordings.

Magnetic tape recording in the teaching of histopathology.

Magnetic tape recording in the teaching of histopathology.

Scaling tape-recording areal densities to 100 Gb/in2

We examine the issue of scaling magnetic tape-recording to higher areal densities, focusing on the challenges of achieving 100 Gb/in <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> in the linear tape format. The current highest achieved areal density demonstrations of 6.7 Gb/in <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> in the linear tape and 23.0 Gb/in <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> in the helical scan format provide a reference for this assessment. We argue that controlling the head-tape interaction is key to achieving high linear density, whereas track-following and reel-to-reel servomechanisms as well as transverse dimensional stability are key for achieving high track density. We envision that advancements in media, data-detection techniques, reel-to-reel control, and lateral motion control will enable much higher areal densities. An achievable goal is a linear density of 800 Kb/in and a track pitch of 0.2 µm, resulting in an areal density of 100 Gb/in <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> .

High-efficiency Decision for the Problem of series automatic assembly on the basis of task-oriented construction of relations providing multiple increment of assembly system tolerances

The cost price of modern industry products to a considerable extent is defined by high labour-consuming character of assembly operations. The same we can say about magnetic tape recorder manufacturing; their assembly automation is hampered by often replacement of articles. Methods are worked out, which allow to estimate technical possibility and economical advisability of their assembly automation and to choose optimum structure of flexible manufacturing system. It allowed to create flexible manufacturing systems of module construction for assembly mechanical units.