Open AccessSmall polaron property of polycrystalline Pr0.7(Sr1-xCax)0.3MnO3 series
Author(s) -
Yong Ma
Publication year - 2009
Publication title -
wuli xuebao
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.199
H-Index - 47
ISSN - 1000-3290
DOI - 10.7498/aps.58.4901
Subject(s) - polaron , condensed matter physics , crystallite , materials science , orthorhombic crystal system , grain boundary , electrical resistivity and conductivity , crystallography , crystal structure , chemistry , physics , electron , microstructure , composite material , quantum mechanics , metallurgy
We have synthesized polycrystalline bars of Pr0.7Sr1-xCax0.3MnO3x=00.1…1with a sol-gel method using citrate as an agent, and grown epitaxial thin films of Pr0.7Sr1-xCax0.3MnO3 on 100-oriented substrates of SrTiO3 STO by using pulsed laser deposition PLD . We systemically investigated their lattice structures and electronic transport property. Both polycrystalline and film samples have orthorhombic lattice structure, and their electronic transport behaviors nicely follow a adiabatic small polaron model in high temperature paramagnetic phase when T is larger than the Curie temperature TC. All resistivity data have been fitted by the small polaron model. The fitted results of polycrystalline samples qualitatively agree with that of corresponding film samples. With increasing contents of Ca, polaron hopping energy Ehop increases monotoniccaly, and ρ0 first decreases, then increases. The above results indicate that electronic transport property of high quality polycrystalline samples is less influenced by lattice defects and grain boundaries which are abundant in low quality samples, such that intrinsic small polaron transport behavior can appear in the former.