Title :
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
fDate :
9/1/2002 12:00:00 AM
Abstract :
The magnetic and magnetotransport properties of ultrathin, discontinuous La0.7Ca0.3MnO3 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; La0.7Ca0.3MnO3; 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;
Journal_Title :
Magnetics, IEEE Transactions on
DOI :
10.1109/TMAG.2002.803140
