GdBa_2Cu_(3-x)Fe_xO_(7-δ)超导体系结构相变及拉曼谱特征  

Characteristic of structural phase transition and Raman spectra in GdBa_2Cu_(3-x)Fe_xO_(7-δ) superconductors

作　　者：陈镇平[1] 郭娟[2] 薛人中[1] 薛运才[1] 李涛[1] 石开[1] 王春梅[1] 

机构地区：[1]郑州轻工业学院技术物理系,郑州450002 [2]郑州大学物理工程学院,郑州450052

出　　处：《低温与超导》2010年第10期28-32,共5页Cryogenics and Superconductivity

基　　金：国家自然科学基金(10875107);河南省自然科学基金(082300440080)资助

摘　　要：采用固态反应法制备了GdBa2Cu3-xFexO7-δ(x=0.00-0.30)系列样品,利用X射线衍射、拉曼光谱以及电测量技术对体系的晶体结构、拉曼散射谱特征以及电输运特性进行了系统研究。结果表明,当Fe掺杂量在x=0.05-0.10区间时,体系的晶体结构发生了从正交相到四方相的转变。通过对拉曼光谱中典型振动模的指认及振动模随Fe掺杂量的变化规律,得到了拉曼谱随体系正交-四方结构相变的变化特征:对于具有正交相的x=0.00-0.05样品,拉曼谱具有五个与正交相结构相对应的特征峰;而对于具有四方相的x=0.10-0.30样品,随Fe掺杂量增加,振动模强度变弱,且典型振动模发生了不同程度的展宽或频移。电输运测量表明,随Fe掺杂量的增加,超导临界温度Tc降低,正常态电阻率增加且发生了金属-半导体相变。Polycrystalline samples of GdBa2Cu3-xFexO7-δ（x = 0-0.30） were prepared by conventional solid state reaction method.The crystal structure,Raman spectroscopy and electrical transport properties were investigated systemically by X-ray diffraction（XRD）,Raman spectroscopy and resistivity measurements.XRD results indicated that the crystal structure of the samples evolved a phase transition from orthorhombic to tetragonal in the Fe doping range of x = 0.05-0.10.The results of Raman spectra demonstrated that there were two types of the Raman spectra with different Fe doping content,e.g.one of the samples with the x range from 0.00 to 0.05 had five especial lines related orthorhombic phase;the other of the samples with the x range from 0.01 to 0.30 showed the moving and expanding of Raman lines to different extents matching the tetragonal phase.The resistivity measurements show that the superconducting transition temperature Tc decreases and the normal state resistivity increases accompanied by a metal-semiconductor transition with increasing Fe doping content.

关 键 词：GdBa2Cu3-xFexO7-δ体系 结构相变 拉曼光谱 电输运特性 

分 类 号：O48[理学—固体物理]