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Journal of the Korean Ceramic Society 1999;36(8): 843. |
| La$_{1.6}$Ca$_{1.4}$Mn$_2$O$_{7.07}$의 전기전도특성 |
| 정우환 |
| 호원대학교 전자공학과 |
| Electical Transport Properties of La$_{1.6}$Ca$_{1.4}$Mn$_2$O$_{7.07}$ System |
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| ABSTRACT |
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The dc resistivity dc magnetization and thermopower of layered perovskite La1.6Ca1.4Mn2O7.07 have been studied. The ceramic sample of La1.6Ca1.4Mn2O7.07 undergoes the metal-insulator transition at 120K while a first-order phase transition from a ferromagnetic phase to a paramagnetic phae is observed at 260 K=TC This behavior is quite different from that of the well-known double exchange ferromagnets such as La1-xCaxMnO3 This phenomenon could be understood by considering the effects of the anisotropic double exchange interaction caused by two dimensional Mn-O-Mn networks in this materials. The dc magnetization between 120K and 250K is nearly constant and decreases rapidly with increasing temperature above 250K The measurements of dc resistivity and thermopower indicate that Zener polaron hopping conduction takes place above 260 K. |
| Key words:
Electron-phonon interaction, Jahn-Teller effect, Hopping, Small polaron, Zener polaron |
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