Mechanism of grain-boundary magnetoresistance in Fe3O4 films

被引：63

作者：

Ziese, M ^{[1
]}

Höhne, R ^{[1
]}

Semmelhack, HC ^{[1
]}

Reckentin, H ^{[1
]}

Hong, NH ^{[1
]}

Esquinazi, P ^{[1
]}

机构：

[1] Univ Leipzig, Dept Superconduct & Magnetism, D-04103 Leipzig, Germany

来源：

EUROPEAN PHYSICAL JOURNAL B | 2002年 / 28卷 / 04期

关键词：

D O I：

10.1140/epjb/e2002-00245-3

中图分类号：

O469 [凝聚态物理学];

学科分类号：

070205 ;

摘要：

The magnetotransport properties of magnetite films with different microstructures were investigated in order to identify prerequisites for the attainment of a large tunnelling magnetoresistance in polycrystalline samples. Epitaxial films on MgAl2O4, polycrystalline films on Al2O3 and rough MgAl2O4 substrates and a polycrystalline La0.7Ca0.3MnO3 film on MgO were compared. Although grain boundaries induce a large high-field magnetoresistance in magnetite films, the low-field magnetoresistance characteristic for spin-polarized tunnelling was virtually absent in these samples. Two factors might be responsible for this behaviour: (1) grain boundaries in magnetite are conducting and do not form tunnelling barriers and (2) the spin-polarization near grain boundaries is suppressed due to non-stoichiometry.

引用

页码：415 / 422

页数：8

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