High-density Magnetic Tape Recording Research Articles

A Solenoid Magnetic Integrated Head for Digital Video Recording

A Helical Scan Silicon Head (HSS Head) with a solenoid coil structure has been developed for high density magnetic tape recording. The head structure and the writing process on the media have been numerically simulated. A batch process with an integrated azimuth compatible with the DVC norm (±20°) has been carried out. The HSS Head frequency behavior has been improved by using a laminated magnetic material (Permalloy).

Advanced MP ++ and BaFe ++ tapes

High-density magnetic tape recording has been expected to evolve from oxide particles to metal particles and ultimately to metal thin films which could provide the highest magnetization and the smallest thickness. Recent developments of very small metal particles (MP ++) with very high coercivities and magnetization, coupled with developments in double-coating technology which allow the coating of very thin and smooth particulate magnetic layers, are combined to produce advanced MP ++ tapes that outperform the metal evaporated (ME) tapes, while at the same time offering much greater reliability and lower cost. Micromagnetic simulations of high-density recording, however, show that high magnetization is undesirable at short wavelengths because of demagnetization and the spreading of the transition regions. Barium ferrite (BaFe) particulate coatings have low demagnetization, can support very narrow transitions, and are completely immune to environmental and chemical corrosion, making them the best choice for high-density recording particularly in combination with high-sensitivity MR transducers.

High-density magnetic tape recording by non-tracking method

Conventional helical-scan magnetic recording requires precise head tracking, precise tape path and accurate servo control. We have developed a magnetic tape recording system based on a new concept, the ‘non-tracking method’, which requires less accuracy. By combining double density track scanning and data rearrangement through a memory device, all data can be reproduced in correct order without precise head tracking. When the track pitch is 9.8 μm, the non-tracking method expands the tolerance on head tracking to ±100 μm, while the head tracking tolerance of ±5 μm is needed in conventional recording. Using the non-tracking method, a newly developed rotary head drum loading system called ‘non-loading’ and also a newly developed metal-evaporated tape, we have developed an extremely high density digital audio tape recording system, including a stamp-sized tape cassette and a miniature digital audio recorder. Two hours stereo digital recording is achieved with the small cassette.

High Density Magnetic Tape Recording by Non-Tracking Method

High Density Magnetic Tape Recording by Non-Tracking Method

A New Silicon Integrated Head For High Density Magnetic Tape Recording

A new silicon integrated magnetic head with a very narrow track width has been achieved. A collective process has been used to carry out a vertical gap fabrication which avoids a glass bonding in the gap area, and allows an integrated coil elaboration. Wear behaviour and frequency dependance for reproduced output level have been investigated.

High Density Magnetic Tape Recording by Non-Tracking Method

Conventional helical-scan magnetic recording requires precise head tracking, precise tape path and accurate servo control for them. We have developed a magnetic tape recording system based on a new concept, "Non-tracking Method" which requires less accuracy of them. By combining double track scanning and data rearrangement through a memory divice, all data can be reproduced in correct order without precise head tracking. When track pitch is 9.8μm, the non-tracking method expands the tolerance on head tracking to plus and minus 100μm, while the head tracking tolerance of plus and minus 5μm is needed in conventional recording. Using the non-tracking method, a newly developed rotary head drum loading system which is called "non-tape-loading" and also a newly developed metal-evaporated tape, we have developed a extremely high density digital audio tape recording system, including a stamp-sized tape cassette and a tiny digital audio recorder. Two hours stereo digital recording is realized with the tiny cassette.

Magnetic and thermomagnetic analysis of metal evaporated tape

Metal evaporated (ME) tape is being developed as an advanced medium for high-density magnetic tape recording. It is produced by evaporation in an oxygen atmosphere, and consists of very small Co and CoNi crystallites intermingled with oxides of Co and Ni. The angle of incidence of the vapor flux is varied continuously during deposition, imparting to the film a distinct curved columnar structure. Previous studies have measured the angular dependence of the coercivity and remanence out of the plane of the tape in order to determine the preferred direction of magnetic anisotropy and the mechanism of magnetization reversal in these films. These studies, however, do not take into account the demagnetizing field. In this study, we used a two-dimensional vector vibrating-sample magnetometer (VSM) to obtain the correct angular dependence of the coercivity and of the remanent magnetization. Our results show that magnetization reversal near the easy axis proceeds by incoherent rotation, and not by domain-wall displacement as suggested by other investigators. We also measured the torque characteristics in the three principal planes and used them to determine the magnitude and angle of the uniaxial magnetic anisotropy in these films. To understand the origin of the magnetic anisotropy, we studied the temperature dependence of Ms and Hc over the range of −100 to +100 °C. We found that Ms is essentially independent of temperature in this range, while Hc has a very large negative temperature coefficient (about 6 Oe/°C). This implies that it is primarily the crystalline anisotropy of the Co and CoNi crystallites which controls the coercivity of these films, and not the shape of the distinct columnar structure or any shape contribution of the crystallites themselves.

Plasma-enhanced vacuum evaporation of perpendicular Co-Cr magnetic thin films

A novel plasma-enhanced vacuum evaporation process is described for the fabrication of perpendicular Co-Cr thin films for high-density magnetic tape recording. The plasma is excited by an RF coil placed between the source and substrate and is supported by the metal evaporant itself without the need for a carrier gas. The primary effect of the plasma is to increase the perpendicular coercivity, thus allowing a reduction in substrate temperature for better compatibility with low-temperature (and cheaper) polymer supports. It is found that Cr concentration, substrate temperature, and substrate surface preparation are critical to the development and control of perpendicular magnetic characteristics. Transmission electron microscopy (TEM) cross-section analysis reveals a slight increase in grain diameter from film bottom to top, even for films with well-oriented initial layers. A survival-of-the-tallest grain growth model in the high-mobility limit is proposed to explain some of the observed features. >

Peak-shift study in high-density magnetic tape recording

This paper examines the influence of magnetic tape, read-write head, and other recording parameters on peak shift encountered in high-density recording. In particular, the effect of prior erase polarity on peak shift is discussed. A technique for examining the remanent moment in a sample of the recorded tape track as a function of write current, density, and angle from the plane of the oxide coating is described.