Magnetic viscosity in iron-rhodium nanowires

Authors
Riva, Julieta Soledad; Pozo Lopez, Gabriela del Valle; Condo, Adriana Maria; Levingston, Jorge Matías; Fabietti, Luis Maria Rodolfo; Urreta, Silvia Elena
Publication Year
2017
Language
English
Format
article
Status
Published version
Description
Noble/transition bimetallic nanowires of nominal composition Fe90Rh10 are AC electrodeposited into 20 nm diameter hexagonally self-assembled alumina nanopores. Nanowires about 18 nm in diameter and 1 μm long are polycrystalline and multiphase. Wires contain α-Fe grains and very small grains of the ClCs-type α′-Fe(Rh) phase. The room temperature magnetization mechanism and the thermal stability of nanowire magnetic configurations are further investigated by measuring the dependence of the coercive field on the applied field sweeping rate R. From these data a mean fluctuations field value of μ0HFR = (9.0 ± 0.5) mT is obtained (at coercivity) and an effective activation magnetic moment μac = 5400 μB is estimated, with μB the Bohr magneton. At the coercive field (about 45 mT) the resulting activation lengths become lAC ≈ 6.4 and 6.7 nm for α-Fe and α′-Fe(Rh), respectively. Assuming an effective magnetic anisotropy, considering magnetostatic shape contributions in addition to the magnetocrystalline one, the domain wall thickness δw in α-Fe grains and in the α′-Fe(Rh) become δwFe = 13.4 nm and δwFeRh = 10.9 nm respectively. These values are comparable to the activation lengths estimated at the coercive field in each phase. These facts strongly indicate that irreversible polarization reversal in these nanowires takes place by local curling, involving localized nucleation modes.
Fil: Riva, Julieta Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; Argentina
Fil: Pozo Lopez, Gabriela del Valle. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; Argentina
Fil: Condo, Adriana Maria. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina
Fil: Levingston, Jorge Matías. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Nacional de Tecnología Industrial; Argentina. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; Argentina
Fil: Fabietti, Luis Maria Rodolfo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; Argentina
Fil: Urreta, Silvia Elena. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; Argentina
Subject
FE-RH POLYCRYSTALLINE NANOWIRES
FLUCTUATIONS FIELD
MAGNETIC VISCOSITY
MAGNETIZATION MECHANISM
Astronomía
Ciencias Físicas
CIENCIAS NATURALES Y EXACTAS
Access level
Restricted access
License
https://creativecommons.org/licenses/by-nc-sa/2.5/ar/
Repository
CONICET Digital (CONICET)
Institution
Consejo Nacional de Investigaciones Científicas y Técnicas
OAI Identifier
oai:ri.conicet.gov.ar:11336/64106