Giant magnetoresistance in Co-Fe-Cu granular ribbons

Abstract

The structure and magnetoresistance of as-quenched and annealed Co 15−x Fe x Cu 85 (x = 0, 3, 6, 9, 12, 15) granular alloys have been investigated. Co-Fe-Cu nanoparticles with sizes in the range of 2-3 nm, 10-20 nm and ∼100 nm are embedded in a Cu matrix in Co-Fe-Cu granular ribbons. The giant magnetoresistance of the granular alloys decreases with increasing Fe content. The Co-Fe-Cu nanoparticles with large size result in a decrease of the number of nanoparticles, the interfaces for spin-dependent scattering of electrons and thus the magnetoresistance.

Mixing enthalpies of liquid alloys and thermodynamic assessment of the Cu–Fe–Co system

“…8b). This prediction agrees well with experimental data, according to which the Cu 0.85 Fe 0.03 Co 0.12 [4] and Cu 0.9 Fe 0.05 Co 0.05 melt-spinning alloys [5] contained one phase: γ(Cu). Line shows that the supersaturated γ(Fe,Co) phase can be obtained at x Cu < 0.4.…”

“…The supersaturated γ(Cu) solution was obtained in Cu 0.85 Fe 0.03 Co 0.12 [4] and Cu 0.9 Fe 0.05 Co 0.05 [5] alloys by liquid quenching.…”

“…Electrodeposited copperiron-cobalt alloys with high magnetic properties and near-zero magnetostriction hold much promise for the production of thin-film recording heads [3]. Giant magnetoresistance is observed in melt-quenched [4,5] and mechanically alloyed [6,7] nanocrystalline alloys of this system. Phase equilibria involving the liquid phase in the Cu-Fe-Co system are of special interest for metallurgy in view of producing steels with low susceptibility to surface fissure in the rolling process [8] and regeneration of cobalt and copper from slag [9].…”

Magnetic behavior of nanocrystalline Cu–Ni–Co alloys prepared by mechanical alloying and isothermal annealing

“…The underlying principle of mechanical alloying is to deform the material under the area of impact between the colliding media leading to storage of energy by plastic deformation [2]. The process has been successfully employed in the synthesis of a wide range of novel materials including the nanocrystalline magnetic alloys [3][4][5][6][7][8]. Genesis of the attractive magnetic properties in such alloys is attributed to the coupling among the hard and soft magnetic phases and separation of magnetic moments by nonmagnetic phases giving rise to spin dependent scattering of conduction electron(s) at the interfaces as well as within the magnetic particles [1,2].…”

Effect of isothermal treatments on the magnetic behavior of nanocrystalline Cu–Ni–Fe alloy prepared by mechanical alloying

“…During the last decade ultrafine/nanocrystalline phase dispersed nonmagnetic matrix composites have yielded a wide range of magnetic properties of technological interest [1][2][3][4]. Genesis of the magnetic properties of such composite microstructures are attributed to the relative orientation of the magnetic moments separated by a nonmagnetic layer/ grains and the spin dependent scattering of the conduction electrons at the interfaces between the magnetic and nonmagnetic phases as well as within the magnetic particles [1][2].…”