Bibliographic Citation

 
US 5,824,165/A/
Giant magnetoresistive heterogeneous alloys and method of making same
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10/20/1998
PAN: US patent application 8-526,745
Bernardi, J.J.; Thomas, G.; Huetten, A.R.
University of California
USDOE, Washington, DC (United States)
AC03-76SF00098
36 MATERIALS SCIENCE; MAGNETORESISTANCE; MAGNETIC FIELDS; HYSTERESIS; MICROSTRUCTURE; ALLOYS; EUTECTICS; DESIGN
Univ. of California, Oakland, CA (United States)
The inventive material exhibits giant magnetoresistance upon application of an external magnetic field at room temperature. The hysteresis is minimal. The inventive material has a magnetic phase formed by eutectic decomposition. The bulk material comprises a plurality of regions characterized by (a) the presence of magnetic lamellae wherein the lamellae are separated by a distance smaller than the mean free path of the conduction electrons, and (b) a matrix composition having nonmagnetic properties that is interposed between the lamellae within the regions. The inventive, rapidly quenched, eutectic alloys form microstructure lamellae having antiparallel antiferromagnetic coupling and give rise to GMR properties. The inventive materials made according to the inventive process yielded commercially acceptable quantities and timeframes. Annealing destroyed the microstructure lamellae and the GMR effect. Noneutectic alloys did not exhibit the antiparallel microstructure lamellae and did not possess GMR properties. 7 figs.

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