Mechanism of Insulator-Metal Transition in La2/3 Ca1/3MnO3:Collapse of Small Polaron
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
Mechanism of Insulator-Metal Transition in La2/3 Ca1/3MnO3:Collapse of Small Polaron
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
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.
(Magnetic phase boundaries (including classical and quantum magnetic transitions, metamagnetism, etc.))
引用本文:
LIU Ning;SUN Yang;ZHANG Yu-Heng. Mechanism of Insulator-Metal Transition in La2/3 Ca1/3MnO3:Collapse of Small Polaron
[J]. 中国物理快报, 2001, 18(7): 957-959.
LIU Ning, SUN Yang, ZHANG Yu-Heng. Mechanism of Insulator-Metal Transition in La2/3 Ca1/3MnO3:Collapse of Small Polaron
. Chin. Phys. Lett., 2001, 18(7): 957-959.
2001, Vol. 18 
