【作者】 郝颖萍； 陈祥磊； 成斌； 许红霞； 韩荣典； 翁惠民； 杜淮江； 叶邦角；

【Author】 HAO Ying-ping,CHEN Xiang-lei,CHENG Bin,XU Hong-xia,HAN Rong-dian,WENG Hui-min DU Huai-jiang,YE Bang-jiao (Department of Modern Physics,University of Science and Technology of China,Hefei 230026,P.R.China)

【机构】 中国科学技术大学近代物理系核固体物理实验室；

【摘要】 首次用正电子湮没技术研究了新的铁基高温超导体SmFeAsOl-xFx,测量了SmFeAsOl-xFx的常温正电子寿命谱以及随温度变化的多普勒展宽谱,并在广义梯度近似(GGA)基础上进行了正电子寿命计算,寿命测量值与理论计算值较吻合;母体样品的多普勒展宽S参数在相变附近呈现出一个跳跃,而超导样品则在超导相和正常相呈现出不同的S-T斜率,S-W曲线的线性表明超导转变并没有引起缺陷类型的改变。更多还原

【Abstract】 SmFeAsO1-xFx superconductor was first studied by Positron lifetime spectra at room temperature and temperature dependent of Doppler-broadening spectra,meanwhile,surperposed-Neutral-Atom model and Finite-Difference method(SNA-FD) are used to calculate the positron lifetime of single crystal SmFeAsO and SmFeAsF samples with different types of vacancies.The calculated positron bulk lifetime in polycrystalline SmFeAsOxF1-x agrees well with the experimental results.The temperature dependence of S parameter of the parent sample is well fitted with two straight lines separated at about 150K indicates that a phase transition occurred,while,the temperature dependence of S parameter of the superconductor sample shows two different slopes before and after superconductivity transition.The linearity S-T plot shows one-type of defects appears in the superconductor sample through the superconductivity transition.更多还原