High-pressure torsion for production of magnetoresistance in Cu–Co alloy

The process of high-pressure torsion (HPT) was applied to control the size and distribution of ferromagnetic Co particles in a Cu–Co alloy. Electron probe microanalysis, X-ray diffraction analysis, and transmission electron microscopy confirmed that the Co particles were significantly refined through fragmentation and dissolved with intense straining by HPT. Magnetoresistance appeared by *2.5% at 77 K with an isotropic feature corresponding to giant magnetoresistance (GMR). It is demonstrated that HPT is a potential process for creating GMR in the Cu–Co alloy prepared by conventional ingot metallurgy.