Spin hopping in ultrathin La-Ca-Mn-O films

Author

Ziese, M. ; Han, K.-H. ; Esquinaz, P.

Author_Institution

Dept. of Supercond. & Magnetism, Leipzig Univ., Germany

Volume

38

Issue

5

fYear

2002

fDate

9/1/2002 12:00:00 AM

Firstpage

2898

Lastpage

2900

Abstract

The magnetic and magnetotransport properties of ultrathin, discontinuous La_0.7Ca_0.3MnO₃ films were studied. The zero field resistivity indicates the granular nature of the film in agreement with atomic force microscopy imaging and the strongly reduced magnetization. The magnetoresistance is very large exceeding the theoretical limit for spin-polarized tunneling in granular ferromagnets. A modification of this model is presented that might explain these large magnetoresistance values.

Keywords

calcium compounds; colossal magnetoresistance; electron spin polarisation; ferromagnetic materials; lanthanum compounds; magnetic thin films; tunnelling; La_0.7Ca_0.3MnO₃; atomic force microscopy imaging; discontinuous films; granular film; large magnetoresistance values; magnetic properties; magnetic-field dependence; magnetotransport properties; pulsed laser ablation; resistor network model; spin hopping; spin-polarized tunneling; strongly reduced magnetization; superparamagnetic interactions; temperature dependence; ultrathin magnetic films; weakly connected grains; zero field resistivity; Atomic force microscopy; Conductivity; Electrical resistance measurement; Magnetic field measurement; Magnetic films; Magnetic properties; Saturation magnetization; Superconducting magnets; Temperature distribution; Tunneling magnetoresistance;

fLanguage

English

Journal_Title

Magnetics, IEEE Transactions on

Publisher

ieee

ISSN

0018-9464

Type

jour

DOI

10.1109/TMAG.2002.803140

Filename

1042403