3000% high-field magnetoresistance in super-lattices of CoFe nanoparticles

JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS

卷:320

Letter

Tan, Reasmey P.¹  Carrey, Julian¹  Respaud, Marc¹  Desvaux, Celine²  Renaud, Philippe²  Chaudret, Bruno³ 

[1] CNRS, UPS, INSA, IRSAMC,LPCNO, F-31077 Toulouse, France

[2] Freescale Semicond, F-31023 Toulouse, France

[3] CNRS, Chim Coordinat Lab, F-31077 Toulouse 4, France

关键词: magnetoresistance;    nanoparticles;    Arrays;    CoFe;    coulomb blockade;   

DOI  :  10.1016/j.jmmm.2007.11.010

来源: Elsevier

【 摘 要 】

We report on magnetotransport measurements on millimeter-large super-lattices of CoFe nanoparticles surrounded by an organic layer. Electrical properties are typical of Coulomb blockade in three-dimensional arrays of nanoparticles. A large high-field magnetoresistance, reaching up to 3000%, is measured between 1.8 and 10 K. This exceeds by two orders of magnitude magnetoresistance values generally measured in arrays of 3d transition metal ferromagnetic nanoparticles. The magnetoresistance amplitude scales with the magnetic field/temperature ratio and displays an unusual exponential dependency with the applied voltage. The magnetoresistance abruptly disappears below 1.8 K. We propose that the magnetoresistance is due to some individual paramagnetic moments localized between the metallic cores of the nanoparticles, the origin of which is discussed. (C) 2007 Elsevier B.V. All rights reserved.

【 授权许可】

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