Hopping conductivity in one-dimensional Ca/sub 3/Co/sub 2/O/sub 6/ single crystals
We studied the electronic conductivity and magnetic properties of quasi-one-dimensional Ca₃Co₂O₆ single crystals. The results evidence a variable range hopping conductivity with temperature-induced crossover between one-dimensional (intrachain) and three-dimensional (3D) transport and the opening of...
| Autores: | , , , , , |
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| Tipo de recurso: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 2002 |
| País: | Brasil |
| Institución: | Universidade Federal do Rio Grande do Sul (UFRGS) |
| Repositorio: | Repositório Institucional da UFRGS |
| Idioma: | inglés |
| OAI Identifier: | oai:www.lume.ufrgs.br:10183/103927 |
| Acceso en línea: | http://hdl.handle.net/10183/103927 |
| Access Level: | acceso abierto |
| Palabra clave: | Materiais antiferromagnéticos Compostos de cálcio Magnetorresistência gigante Materiais ferromagnéticos Modelo de heisenberg |
| Sumario: | We studied the electronic conductivity and magnetic properties of quasi-one-dimensional Ca₃Co₂O₆ single crystals. The results evidence a variable range hopping conductivity with temperature-induced crossover between one-dimensional (intrachain) and three-dimensional (3D) transport and the opening of a Coulomb gap in the d bands along with the ferromagnetic intrachain ordering. At low temperatures, an applied magnetic field induces a large negative magnetoresistance (MR) in apparent dissociation with the 3D magnetic ordering. Both spin-dependent hopping and field-induced suppression of the Coulomb gap are discussed. The electronic hopping parameters we infer agree remarkably with the accessible Co sites. Surprising narrow peaks corresponding to a transient resistivity decrease are observed on the MR curves. We discuss these in terms of peculiar in-plane magnetization states in an Ising-like Heisenberg antiferromagnetic triangular lattice during the magnetization reversal. |
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