Title:
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Tunneling magnetoresistance in Co-ZrO2 granular thin films
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Author:
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Hattink, Bart Jan; García del Muro y Solans, Montserrat; Konstantinovic, Zorica; Batlle Gelabert, Xavier; Labarta, Amílcar
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Other authors:
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Universitat de Barcelona |
Abstract:
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Granular films composed of well defined nanometric Co particles embedded in an insulating ZrO2 matrix
were prepared by pulsed laser depositon in a wide range of Co volume concentrations 0.15 x 0.43.
High-resolution transmission electron microscopy TEM showed very sharp interfaces between the crystalline
particles and the amorphous matrix. Narrow particle size distributions were determined from TEM and by
fitting the low-field magnetic susceptibility and isothermal magnetization in the paramagnetic regime to a
distribution of Langevin functions. The magnetic particle size varies little for Co volume concentrations x
0.32 and increases as the percolation limit is approached. The tunneling magnetoresistance TMR was
successfully reproduced using the Inoue-Maekawa model. The maximum value of TMR was temperatureindependent
within 50–300 K, and largely increased at low T, suggesting the occurrence of higher-order
tunneling processes. Consequently, the tunneling conductance and TMR in clean granular metals are dominated
by the Coulomb gap and the inherent particle size distribution. |
Subject(s):
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-Superfícies (Física) -Superconductivitat -Pel·lícules fines -Surfaces (Physics) -Superconductivity -Thin films |
Rights:
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(c) The American Physical Society, 2006
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Document type:
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Article Article - Published version |
Published by:
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The American Physical Society
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