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CZT/FeXN multilayer systems

IP.com Disclosure Number: IPCOM000010859D
Original Publication Date: 2003-Jan-28
Included in the Prior Art Database: 2003-Jan-28
Document File: 3 page(s) / 13K

Publishing Venue

IBM

Abstract

Disclosed are multilayered and laminated soft magnetic materials. They consist of magnetic materials laminated with thin dielectric spacers. The magnetic materials itself are multilayers of an amorphous Co-alloy and Fe-Nitrites. The full multilayer can be deposited in a sputtering tool. These materials exhibit tunable magnetic properties and a high degree of eddy current suppression. Therefore they are of high interest for write applications in thin film read/write CR/W heads.

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CZT/FeXN multilayer systems

  Up to now, the main requirement for a magnetic write head was to be able to produce a magnetic field strong enough to write on a high coercivity media. As the writing frequency is also increasing, a new demand for a good high frequency response is being added. The main limitation in fast magnetic recording is the presence of Eddy currents on the yoke of the write head which results to a limitation of the data rate.

    A multilayer structure for use in thin film read/write heads is disclosed. The structure consists of magnetic layers laminated by a dielectric spacer (here Al2O3) and has the following form:
[CZX1/FeX2N]xN1/Al2O3)xN2

    Where CZX1: amorphous Cobalt alloy (X1=Cr, Ta, Rh etc), FeX2N: iron nitride (X2=Al, Ta, etc), N1: number of magnetic bilayers, Al2O3: alumina, the dielectric spacer, N2: number of laminations

Al2O3

Fig1. Example of the multilayered and laminated structure. Here, N1 = 3 and N2 = 2.

    By adjusting N1 as well as the thickness ratio between the amorphous Cobalt alloy and the Iron nitride the magnetic properties of the structure can be adjusted and fine tuned. Such properties include Ms, Hc, anisotropy Hk and magnetostriction. Amorphous Cobalt alloy exhibits excellent soft magnetic properties namely low coercivities for hard and easy axis and near zero magnetostriction. Also its resistivity is 5 times higher compared to permalloy and magnetic anisotropy field (Hk) is around 18Oe. High resistivity has a reducing effect as far as Eddy currents are concerned. On the other hand, Iron nitrides can have very high magnetic moment (24 kGauss). In Fig.2 the effect of combining FeN with CZT(CoZrTa) in a multilayer can be seen. These films have a total thickness o...