Open AccessPositron annihilation lifetime study of SmFeAsO superconductor
Author(s) -
Hao Ying-Ping,
Xianglei Chen,
Bin Cheng,
Weiliang Kong,
Xu Hong-Xia,
Du Huai-Jiang,
Bangjiao Ye
Publication year - 2010
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.59.2789
Subject(s) - annihilation , electron , materials science , crystallite , positron annihilation , valence electron , superconductivity , valence (chemistry) , condensed matter physics , positron , core electron , physics , atomic physics , nuclear physics , quantum mechanics , metallurgy
Positron annihilation lifetime spectroscopy (PALS) measurements of SmFeAsO polycrystalline sample were first carried out at 298 K. Two lifetime components of 1516 ps and 2903 ps were obtained. According to two-state capture model, the free annihilation lifetime in polycrystalline SmFeAsO is 1870 ps, which agrees well with the calculated valuein general gradient approximation of 173 ps in SmFeAsO single crystal. Superposed-neutral-atom model and the finite-difference method (SNA-FD) were used to calculate the positron annihilation information in single-crystal SmFeAsO. The results show that the ratio of annihilation rate with valence electrons to annihilation rate with core electrons is 106, while the ratio of annihilation rate with electrons from Fe, As, Sm, and O atoms are 1∶13∶12∶1