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A multi-tapped magnetoresistive (MR) stripe has been commercially fabricated as a tape head for evaluation as a potential tracking sensor for magnetic tape systems with dedicated servo. In this approach, two adjacent MR elements sharing a common bias current are each positioned halfway over a single 17 um wide servo track. The head leads provide signals from each of the MR elements which are separated 1.25 um by permanent magnets that provide longitudinal bias. Since this servo configuration uses a differential sensor with a simple square wave tracking pattern, the system can allow self-servo formatting. The evaluation of these heads on a Metrum test stand with 1550 Oe Sony MP media have allowed an estimate of the finest track pitch servo system that could be supported by such a sensor. Two sources of PES error, media noise and PES nonlinearity, have been quantified, and projections of system performance at high tape speeds and narrow trackwidths have been made. With this scheme it seems feasible to reach a 2 um track pitch, but to do so, a non-linear PES fit must be used. Furthermore, to maintain high SNR, the sensor should not be operated in a manner such that it needs to be scaled down in size as the trackwidth shrinks, favoring a so-called multiposition operation scheme. Index Terms - Tape Recording, Tape Heads, Tracking Servos, Position Error Signal, Magnetoresistive Heads.

Shielded spin-valve tape heads with permanent magnet stabilization are described. Final MR of 3.5% is shown on heads with trackwidths of 5 and 9 [[micro]meter], and sensor heights of 0.5, 1.0 and 1.5 [[micro]meter]. Heads are characterized on 1/2[inch] DLT-IV tape up to 180 kfci. For isolated transitions the heads show a [PW.sub.50] of 0.8 [[micro]meter] (pulse broadening due to partial head saturation) and a baseline shift [approximately]10% that can be positive or negative, and is related with shield remanence and transfer curve hysteresis. At 120 kfci, head output for a sense current of 3 to 4 mA is [approximately] 1 [mV.sub.pp] (up to 30% of the output at 30 kfci). At high linear densities, signal loss is 0.24 dB/kfci for a 0.35 [[micro]meter] shield-to-shield spacing ([D.sub.50] of 80[approximately]100 kfci). At low linear densities the head is partially saturated, and above 60 kfci harmonic distortion is lower than -20 dB. Index Terms - magnetic recording/reading heads, magnetoresistive materials and devices, spin valve heads, tape recording.

This paper describes the design, fabrication and performance of an advanced multi-channel tape head for linear digital video applications. The heads were batch fabricated on AlTiC substrates using conventional thin film processing techniques. Each head comprised an array of 16 channels, with each channel consisting of a merged MR reader/inductive writer structure. Two separate head designs were manufactured to investigate improved areal density recording. One type had a channel pitch of 150 um and did not employ a servo scheme. The second type had a channel pitch of 112.5 um and employed a closed loop servo mechanism. After machining and assembly, fully functional heads were employed to write data onto conventional 1650 Oe metal particulate tape media using RLL (1,7) code at a track density of approximately 1350 tpi and a linear transition density of 102 kpbi resulting in an areal density of 138 Mb/[in.sup.2]. The heads exhibited good output, symmetry, resolution and overwrite. The data indicates that with careful process control, it is feasible to manufacture multi-channel tape heads using thin film processing techniques. Index Terms - Tape Recording, Tape Heads, Multichannel Recording, Magnetoresistive Heads

A recently developed, advanced multi-track tape head for operation in a next generation, high performance tape drive is described. This head features full thin film write elements with high moment, cobalt-based pole materials for recording on high coercivity metal particle (MP) tape, together with narrow track, shielded, dual-stripe magnetoresistive (DSMR) read elements. This presentation will discuss the global design philosophy of the head with particular attention to the design and recording performance of the read and write elements in a tape environment. The head is capable of recording 288 tracks on half-inch, MP tape of 1625-1850 Oe coercivity at a recording density of 65 kfci. The system operates with 16 parallel data channels and includes full multi-element active track following servo. The head can be used in a full start-stop mode and read verify on the fly (read-while-write) hi-directional operating modes.

A study of a series of progressively aligned metal particle tape samples has been undertaken. Our data indicates that increasing the orientation, desirable for better recording performance, has been found to increase thermal effects at both DC and high frequencies. The implications of this are that larger head fields are required to write high frequency transitions on more aligned media. The experimental results are compared to the switching model suggested by el Hilo to determine the thermal stability factor [KV.sub.m]/kT of the samples. Index Terms--interactions, magnetisation reversal, metal particles, orientation, pulsed magnetic fields, thermal stability

A self-consistent recording simulator combined with a micromagnetic MR head model is developed to study write equalization in tape recording. The simulation study presented in this paper focuses on the understanding of the magnetization configurations resulted from write equalization and the impact on the write and read nonlinearity. It is found that the write equalization process results in a demagnetized state in otherwise saturated regions. The model analysis combined with an EPR4 channel demonstrates how both write and read linearity of the system are improved. Index Terms--write equalization, tape recording, nonlinearity.

Lower flying height provides higher recording density in hard disk drives. The gas lubricating film thickness (flying height) between the magnetic head and the disk has been reduced to under 50 nm and various designs for the air bearing surface of the head slider have been discussed. To obtain high flying stability in very Low flying conditions, it is important to achieve a high air bearing stiffness and to reduce the flying height fluctuation during head motion over the disk surface. We simulated the flying characteristics of the slider with shallow step air bearing pads and compared the simulated results with the experimental results. We also analyzed the air bearing stiffness, the flying characteristics during seek motion, the altitude sensitivity and the flying fluctuation due to the major manufacturing tolerances. The newly designed sliders have good characteristics for achieving a flying height around 25 nm. Index Terms--head disk interface, air bearing surface, flying head, slider design

As the magnetic recording areal density approaches 10 Gb/[in.sup.2], the mechanical spacing between the head and the disk is expected to reduce rapidly below 20 nm. This leads to an increase of head-disk interaction which may induce an unacceptable level of interfacial wear. in this study experimental air bearing sliders were designed and fabricated to fly in close proximity or substantial contact with the disk. The durability of the interface decreased with decreasing mechanical clearance. The amount of head and disk wear was determined. The metrology and some of the challenges in maintaining a functional interface are presented. Index terms--head-disk interface, contact recording, tribology.

This paper presents a novel micro-machined dual slider-suspension design for near-contact/contact recording and discusses a few crucial issues for this type of designs, including the shock/adhesion-induced deflection of micro-suspension and vibrations of a secondary slider which uses a partial contact air bearing. The work is aimed to provide a reliable, durable and stable mechanical head-disk interface of 5-15 nm spacing and to support 30-40 Gb/[in.sup.2] areal densities or beyond magnetic recording. Index Terms--Magnetic recording, head-disk spacing, slider design, HDI dynamics.