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Mechanism of Insulator-Metal Transition in La2/3 Ca1/3MnO3:Collapse of Small Polaron
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| LIU Ning1,2;SUN Yang1;ZHANG Yu-Heng1 |
| 1Structure Research Laboratory, University of Science and Technology of China, Hefei 230026
2Department of Physics, Suzhou Normal College, Suzhou, Anhui 234000
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| Cite this article: |
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LIU Ning, SUN Yang, ZHANG Yu-Heng 2001 Chin. Phys. Lett. 18 957-959 |
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Abstract The insulator-metal (I-M) transition in colossal magnetoresistance material La2/3 Ca1/3MnO3 has been studied by electrical transport, magnetization and electron spin resonance (ESR) measurements. Around the I-M transition, the ESR signal shows a crossover from paramagnetic resonance line to ferromagnetic resonance line, which implies a coexistence of localized small polarons and itinerant carriers during the I-M transition. Based on the concept of ‘small polaron collapse’, a two-phase model is proposed to quantitatively describe the electrical transport behaviour across the insulator-metal transition. The calculations of resistivity in different applied magnetic fields have close trends with the experimental data, which strongly proves that the I-M transition results from the collapse of small polarons and two phases coexist during the transition.
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| Keywords:
72.15.Gd
75.50.Cc
75.30.Kz
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Published: 01 July 2001
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| PACS: |
72.15.Gd
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(Galvanomagnetic and other magnetotransport effects)
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75.50.Cc
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(Other ferromagnetic metals and alloys)
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75.30.Kz
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(Magnetic phase boundaries (including classical and quantum magnetic transitions, metamagnetism, etc.))
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