Magnetization mechanisms in ordered arrays of polycrystalline Fe{sub 100−x}Co{sub x} nanowires

Journal Article · Thu May 28 00:00:00 EDT 2015 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4921701· OSTI ID:22410249

Viqueira, M. S.; Bajales, N. ^[1]; Urreta, S. E. ^[2]

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1. Instituto de Física Enrique Gaviola–CONICET, Universidad Nacional de Córdoba, Ciudad Universitaria, 5000 Córdoba (Argentina)
2. Facultad de Matemática, Astronomía y Física, Universidad Nacional de Córdoba, Ciudad Universitaria, 5000 Córdoba (Argentina)

Magnetization reversal processes and coercivity mechanisms in polycrystalline Fe{sub 100−x}Co{sub x} nanowire arrays, resulting from an AC electrodeposition process, are investigated. The array coercivity is described on the basis of polarization reversal mechanisms operating in individual wires, under the effect of inter-wire dipolar interactions described by a mean field approximation. For individual wires, a reversal mechanism involving the nucleation and further expansion of domain-wall like spin configuration is considered. The wires have a mean grain size larger than both the nanowire diameter and the exchange length, so localized and non-cooperative nucleation modes are considered. As the Co content increases, the alloy saturation polarization gradually decreases, but the coercive field and the relative remanence of the arrays increase, indicating that they are not controlled by the shape anisotropy in all the composition range. The coercive field dependence on the angle between the applied field and the wire long axis is not well described by reversal mechanisms involving nucleation and further displacement of neither vortex nor transverse ideal domain walls. On the contrary, the angular dependence of the coercive field observed at room temperature is well predicted by a model considering nucleation of inverse domains by localized curling, in regions smaller than the grain size, exhibiting quite small aspect ratios as compared to those of the entire nanowire. In arrays with higher Co contents, a transition from an initial (small angle) localized curling nucleation mechanism to another one, involving localized coherent rotation is observed at about π/4.

• OSTI ID: 22410249
• Journal Information: Journal of Applied Physics, Vol. 117, Issue 20; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
COBALT ALLOYS
COERCIVE FORCE
COMPARATIVE EVALUATIONS
CONCENTRATION RATIO
ELECTRODEPOSITION
GRAIN SIZE
IRON BASE ALLOYS
MAGNETIZATION
MEAN-FIELD THEORY
NANOWIRES
NUCLEATION
POLARIZATION
POLYCRYSTALS
SPIN
TEMPERATURE RANGE 0273-0400 K
VORTICES