Enhanced tunneling magnetoresistance ofFe−Al2O3granular films in the Coulomb blockade regime
| Autor: | T Zhu, YJ Wang |
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| Rok vydání: | 1999 |
| Předmět: | |
| Zdroj: | Physical Review B. 60:11918-11921 |
| ISSN: | 1095-3795 0163-1829 |
| DOI: | 10.1103/physrevb.60.11918 |
| Popis: | Tunneling giant magnetoresistance (MR) effects in Fe-Al2O3 granular films that were prepared by cosputtering have been reported. MR of the samples have been measured over a wide range of volume fractions of Fe (x) and it takes a maximum of 4.4% at room temperature for the film with x = 0.45 when a magnetic field of 10 kQe was applied parallel to the film plane. The small tunneling MR at room temperature can be explained by the results of spin-hip processes. However, the observed temperature dependence of MR reveals an enhanced tunneling MR effect in the Coulomb blockade regime. The MR for x = 0.45 remarkably increases with decreasing temperature resulting in MR = 20.1% at 5 K, which is larger than the theory value for Fe-based granular systems. This enhancement of MR effect in the Coulomb blockade regime seems to arise not only from the suppression of the spin-flip process with decreasing temperature, but also from the spin dependent cotunneling in the Coulomb blockade regime. [S0163-1829(99)01238-2]. |
| Databáze: | OpenAIRE |
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