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We have investigated the suitability of a number of magnetic films for use as a pole material in MR tape heads. These include nickel iron, cobalt tantalum zirconium, and two cobalt iron alloys. Heads were fabricated using these alloys as pole materials. The heads were tested both for their electrical performance and for their wear characteristics.

In this article, we present data on the critical dependence of the magnetic, electrical and microstructural properties of spin-valves (SV) on seed-layer thicknesses. The SV structure is: seed-layer/PtMn 140 A/CoFe 16 A/Ru 8.5 A/CoFe 21 A/Cu 20 A/CoFe 12 A/NiFe 30 A/Ta 30 A, where the seed layer is NiFeCr-CoFe or NiFeCr/NiFe. As the thickness of the bilayer seed layer is varied, it is found that a critical thickness boundary exists across which the film properties are radically different. The GMR ratio increased from 7% to 14% (a 100% change), the sheet resistance decreased by about 4 ohms/square and the crystalline texture transitioned from weak to extremely strong (111) texture. The critical thickness boundary is at a combined thickness of 37 A to 40 A. These results suggest a mechanism at the boundary between NiFeCr and CoFe during film growth. A better lattice match between NiFeCr-CoFe, for example, NiFeCr 33 A and CoFe 7 A, generates a strong (111) texture, which enhances the MR% as compared to NiFeCr 33 A./CoFe 6 A. The [H.sub.50] (the field at 50% MR) also exceeds 2000 Oe. This also indicates enhancement of the PtMn fcc to fct transition based on the specifically combined thicknesses of NiFeCr-CoFe. With the NiFeCr-NiFe seed layer, the critical thickness effect is not observed within these thickness ranges. Index Terms--Critical thickness, NiFeCr, PtMn, seedlayer, spin valve.

The effect of texture evolution on the magnetic properties of FeTaN films sputtered on sloping surfaces is examined as substrate bias and slope angle are varied. When either substrate bias increases or [N.sub.2]/Ar flow ratio decreases, the magnetic properties of the films become much softer. X-ray spectra and pole figures show that the increased substrate bias enhances both (110) fiber texture along the film normal and uniform distribution of [002] axes in the film plane. Increased bombardment of Ar ions also results in reduced (110) lattice spacing. An increased (110) peak intensity is similarly observed when the [N.sub.2]/Ar flow ratio is decreased. Index Terms - FeTaN, Magnetic Properties, Substrate Bias, Texture.

Inductively coupled plasma (ICP) reactive ion etching of Al2O3 with fluorine-based gas chemistry in a high density plasma reactor was carried out in an initial investigation aimed at data storage applications. A statistical design of experiments was implemented to optimize etch performance with respect to process variables such as ICP power, platen power, direct current (dc) bias, and pressure. Both soft photoresist masks and hard metal masks were investigated in terms of etch selectivity and surface properties. The reverse power dependence of dc bias on the ratio of ICP to platen power was elucidated. Etch mechanisms in terms of physical and ion enhanced chemical etchings were discussed. The F-based chemistry greatly enhances the etch rate of alumina compared to purely physical processes such as ion milling. Etch rates as high as 150 nm/min were achieved using this process. A practical process window was developed for high etch rates, with reasonable selectivity to hard masks, with the desired profile, and with low substrate bias for minimal damage. [ABSTRACT FROM AUTHOR]

Inductively coupled plasma (ICP) reactive ion etching of [Al.sub.2][O.sub.2] with fluorine-based gas chemistry in a high density plasma reactor is carried out. A practical process window is developed for high etch rates, with reasonable selectivity to hard masks, with the desired profile and with low substrate bias for minimal damage.

Dc magnetron sputtering technique used to deposit FeCo films and their laminations with ultrathin NiFe layers down to 5 Angstrom. Three deposition parameters, including target power, argon pressure, and substrate bias voltage that determine thin film growth dynamics and therefore thin film physical properties is identified for optimization.

FeCo films and their lamination with ultrathin NiFe layers down to 5 Å were deposited using dc magnetron sputtering techniques. Soft magnetic FeCo films were obtained at an optimal target power of 500 W and an optimal deposition pressure of 2 mTorr with high saturation flux density, Bsat>2.4 T, and low easy-axis coercivity, Hce⩽15 Oe, and hard-axis coercivity, Hch⩽3 Oe, at a film thickness of 2000 Å. While the magnetostriction remains at ≚4 × 10-6 the stress was further optimized by applying substrate bias at a controlled level ⩽50 V without sacrificing film magnetic softness. [ABSTRACT FROM AUTHOR]

In this article, we present data on the critical dependence of the magnetic, electrical and microstructural properties of spin-valves (SV) on seed-layer thicknesses. The SV structure is: seed-layer/PtMn 140 Å/CoFe 16 Å/Ru 8.5 Å/CoFe 21 Å/Cu 20 Å/CoFe 12 Å/NiFe 30 Aim 30 Å, where the seed layer is NIFeCr-CoFe or NIFeCr/NiFe. As the thickness of the bilayer seed layer is varied, it is found that a critical thickness boundary exists across which the film properties are radically different. The GMR ratio increased from 7% to 14% (a 100% change), the sheet resistance decreased by about 4 ohms/square and the crystalline texture transitioned from weak to extremely strong (111) texture. The critical thickness boundary is at a combined thickness of 37 Å to 40 Å. These results suggest a mechanism at the boundary between NiFeCr and CoFe during film growth. A better lattice match between NiFeCr-CoFe, for example, NiFeCr 33 Å and CoFe 7 Å, generates a strong (111) texture, which enhances the MR% as compared to NiFeCr 33 Å/CoFe 6 Å. The H50 (the field at 50% MR) also exceeds 2000 Oe. This also indicates enhancement of the PtMn fcc to fct transition based on the specifically combined thicknesses of NiFeCr-CoFe. With the NiFeCr-NiFe seed layer, the critical thickness effect is not observed within these thickness ranges. [ABSTRACT FROM AUTHOR]