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Browse Prior Art Database

Laminated Shields for Thin Film Recording Heads

IP.com Disclosure Number: IPCOM000084170D
Original Publication Date: 1975-Sep-01
Included in the Prior Art Database: 2005-Mar-02
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Hempstead, RD: AUTHOR [+3]

Abstract

Laminated shields for thin-film heads are made by evaporation using permalloy (83% Ni 17% Fe) for magnetic films and titanium, Schott glass 48329, or tantalum for high resistivity nonmagnetic interlayers. The permalloy, layers are 2mu m thick, and each permalloy layer is preferably 500 Angstroms; 2000 Angstroms thick. Interlayer thickness preferably varies between 50 Angstroms and 200 Angstroms. Optimal magnetic properties were obtained with 500 Angstrom thick permalloy and 100 Angstrom thick Schott glass.

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Laminated Shields for Thin Film Recording Heads

Laminated shields for thin-film heads are made by evaporation using permalloy (83% Ni 17% Fe) for magnetic films and titanium, Schott glass 48329, or tantalum for high resistivity nonmagnetic interlayers. The permalloy, layers are 2mu m thick, and each permalloy layer is preferably 500 Angstroms; 2000 Angstroms thick. Interlayer thickness preferably varies between 50 Angstroms and 200 Angstroms. Optimal magnetic properties were obtained with 500 Angstrom thick permalloy and 100 Angstrom thick Schott glass.

The shields are evaporated onto substrates preferably at temperatures of 25 degrees C to 250 degrees C. At low-substrate temperatures, high-intrinsic stress in the permalloy causes film peeling. At substrate temperatures above 50 degrees C no peeling is observed. At a substrate temperature of 150 degrees C, intrinsic plus thermal stress are nearly minimum.

Magnetic properties of laminated shields are better than those of nonlaminated permalloy films, e,g., laminated shields with 40 layers each of 500 Angstrom thick permalloy and 100 Angstrom thick titanium evaporated onto a substrate at 150 degrees C have the following magnetic properties: easy axis coercivity (H(CE)) is 0.55 Oe; hard axis coercivity (H(CH)) is 0.3 Oe; anisotropy field (H(K))is 7.2 0e; permeability is 1,131 at 1MHz, 1,074 at 10MHz, and 609 at 100MHz.

Another example of improved magnetic properties due to lamination, is for laminated shields with 40 layers...