Amorphous Materials for Micrometer and Submicrometer Bubble Domain Technology

Abstract

A review and critique is made of those material and processing issues that pertain to the implementation of micrometer and subrnicrometer bubble devices on amorphous films. Adequate reproducibility and uniformity have been achieved in ternary amorphous films prepared by rf sputtering and their magnetic characteristics are very similar to those of analogous garnet films. Factors that may limit application to the amorphous films include defects and dielectric breakdown in insulating layers, sensitivity to annealing, and larger, but not prohibitive, coercivities. A salient problem common to both garnet and amorphous materials is attainment of sufficiently large values of Q to ensure stable device operation.

3d-4f METALLIC COMPOUNDS.Magnetic moment, magnetic anisotropy and spin-reorientation phase transition in (4f-3d)-intermetallic compounds

“…-Great interest in the magnetic properties of intermetallic compounds of 4f-metals (R) with transition 3d-metals (T) has been displayed in the last 15 years. This is first of all connected with the fact that the (4f-3d)-alloys are used as hard [1] and magnetostrictive [2] magnetic materials, as materials for recording of information using bubble domains [3] as well as for thermomagnetic transducers using spin reorientation [4]. The potential of (4f-3d)-compounds for these purposes is determined by such characteristics as spontaneous magnetization, magnetic anisotropy, magnetostriction and Curie temperature.…”

“…Figure 4 gives as an example the concentration dependence of the anisotropy constants for Er,(Co, -,Fe,),, [lo]. This dependence can be explained if we assume that the anisotropy of these compounds at low temperatures is mainly determined by the Er-sublattice anisotropy, and the crystal field acting on the Er-ions is changed in a complicated way because of an uneven replacement Co and Fe-ions, and o, = -2-'+' e2 < r: ) K,(J), 3 where e is the electronic charge, ( r,' ) is the mean of the 4f-electronic shell radius in I-th power, The agreement between the experimental and calculated Ky(T) is very good, if we take to from [5].…”