Metal evaporated tape: state of the art and prospects

Thin metallic films are the first choice for media in advanced rigid disk systems. For helical scan tape recorders thin metal films have become more important. The high signal-to-noise ratio per unit of track width allows very high densities. The preparation techniques and materials properties of the thin-film coating of metal evaporated (ME) are described. Important aspects are the size of the grains, the geometry of the columnar structure and the associated anisotropy. The consequences for the recording process are explained. Tribological and corrosion properties also help to determine the usefulness of a recording tape. Corrosion, wear, protection layers and lubricating organic films are briefly discussed

Comparison of recording properties of ME tape and thin MP tape with respect to overwrite behavior

Differences between the recording characteristics of thin MP and ME tape are studied. The effect of the thickness reduction of MP tape is also investigated. When thin MP tape (with thickness 140 nm) is compared with ME tape (with thickness 150 nm), we observe a better signal and overwrite response for the ME tape. Through simulations the influence of an easy axis out-of-plane and a different reversal mechanism in ME tape is related to overwrite behavio

Magnetization transitions obtained by deconvolution of measured replay pulses in perpendicular magnetic recording

Magnetization transitions in perpendicular magnetic recording have been calculated from measured replay pulses by a deconvolution algorithm using an analytical expression for the field of a probe head (PH). The transitions appear to be asymmetric whereby a pronounced magnetization peak occurs whose shape depends on the medium coercivity. For the experiments double layer media with double sided probe heads have been used. For the deconvolution only perpendicular head field and medium magnetization components are considered

Track edges in metal-evaporated tape and thin metal-particle tape

MFM images of tracks written in ME and MP tape have been obtained. The analysis of the images concentrated on the track edges. A track written with signals of 0.5 μm wavelength overwrites a part of a track written with a wavelength of 1 μm. The sharpness of the edges was derived from MFM results. It can be seen that the MP sample shows smaller changes in sharpness of the edge with an increasing write current than ME tape. In ME tape, the region between the λ=0.5 μm and the λ=1 μm parts of the track is much wider than the original λ=1 μm edge

The history of consumer magnetic video tape recording, from a rarity to a mass product

Since the Þrst experiments on magnetic recording by Valdemar Poulsen in 1898 the use of this technology has grown tremendously and magnetic storage is used in almost every home in the world. A special challenge was the recording of video signals which need a high bandwidth. In the 1950s, television broadcasts had started which created a need for storage in the broadcast world. The Þrst broadcast recorder was the Quadruplex from Ampex in 1956. Later solutions were found for application in the consumer market. Better mechanics, magnetic tapes and recording heads allowed the mass production of a cheap consumer recorder. The size and weight decreased tremendously and portable camcorders are very common. Recording of broadcasts, video rental and home movies are now very popular. The factors which contributed to the maturing of this technology will be reviewed in this paper

Recording characteristics as a result of the special morphology of ME tape

The performance of ME tape has been studied by assuming a certain morphology of the magnetic layer. The effects of a non-uniform magnetization throughout the depth and an easy-axis out-of-plane are studied and their influence on the recording behavior are investigated. For this purpose a self-consistent recording model is used, in which a Moving-Preisach Stoner-Wohlfarth hysteresis model is implemented. Decreasing the magnetization from the top to the bottom layer could possibly improve the recording characteristics