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Permanent Magnetic Thin Film Material

IP.com Disclosure Number: IPCOM000078295D
Original Publication Date: 1972-Dec-01
Included in the Prior Art Database: 2005-Feb-25
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Lee, K: AUTHOR [+2]

Abstract

Disclosed is the preparation and use of a new permanent magnetic material in thin-film form. This material is single-domain clusters of MnBi(1-x)Sb(x) dispersed in a nonmagnetic matrix of Bi. This material in this configuration has the same high H(c) ( approx. 2 x 10/4/ Oe) as SmCo(5).

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Permanent Magnetic Thin Film Material

Disclosed is the preparation and use of a new permanent magnetic material in thin-film form. This material is single-domain clusters of MnBi(1-x)Sb(x) dispersed in a nonmagnetic matrix of Bi. This material in this configuration has the same high H(c) ( approx. 2 x 10/4/ Oe) as SmCo(5).

The single-domain clusters (or particles) are prepared by depositing successive layers of Bi, Sb and Mn on preheated glass substrates. Subsequently, the layered films are vacuum annealed. Films prepared in this manner contain single-domain regions of MnBi(1-x)Sb(x) which are uniformly dispersed in the plane of the film.

The H(c) for these clusters (or particles) is greater than 2 X 10/4/ Oe at room temperature. The temperature dependence of H(c) shows the same rapid increase with increasing T as the uniaxial anisotropy. This dependence indicates that H(c) = 2K/M for single-domain particles. Substitution of the bulk values for K and M yields values for H(c) comparable to those measured. In addition, M is normal to this film plane and the remanence is 100%.

The range of x for which this effect has been observed is between 0.005 and
0.09. The Sb combines with Mn to form MnSb, and the latter apparently helps to increase H(c) by isolating the clusters of single-domain MnBi. The higher Sb content produces higher values of H(c).

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