【作者】 俞志毅； 叶红娟； 陆卫； 沈学础；

【Author】 Yu Zhiyi,Ye Hongjuan,Lu Wei,Shen Xuechu Laboratory for Infrared Physics,Shanghai Institute of Technical Physics,Academia Sinica.

【机构】 中科院上海技术物理研究所；

【摘要】 <正>近来,由于高Tc超导材料的突破性发现,有关材料制备、物性研究及超导机制等方面的报道迅速增加。远红外光谱技术是研究各类超导材料的能隙及晶格振动行为的方便而有效的手段之一。作者已经详细报导了YBa₂Cu₃O_9-y的远红外反射光谱。本文进一步研究Sr部分代替Ba的高Tc Y(Sr_xBa_1-x)Cu₃O_9-y的远红外反射光谱,以期对Y—Ba—Cu—O系统的超导机理研究提供有用的信息。样品制备采用粉末压片高温烧结方法。X射线衍射测量表明样品为单相Y(Sr_xBa_1-x)₂Cu₃O_9-y（x≈0.5,y≈2）。电阻率及交更多还原

【Abstract】 The far Infrared reflectance spectra of Y(Sr_xBa_1-x)₂Cu₃O_9-y（x=0.5） （T_c=88K） have been measured at temperatures between 4.2K and 300K In the frequency range 50 cm^-1 - 360 cm^-1.Five main phonon structures at 157 cm^-1,176 cm^-1,195 cm^-1,283 cm^-1 and 325 cm^-1 on a continuous background were observed.Two gap-like structures at 144 cm^-1（2Δ/k_BT_C= 2.4 ） and 214 cm^-1（2Δ₂/k_BT_C = 3.5 ） were also observed in the spectra.The far infrared absorption coefficients were calculated from the K-K transformed extinction coefficients of Y(Sr_XBa_1-X)₂Cu₃O_9-y.We suggest that the abovementioned phonon structures are associated with the vibrations of Ba atoms,Sr atoms,Y atoms and the bending vibrations of Cu-O bonds,respectively.The observed two gap-like structures seems to be a reflection of the anisotropy of superconduction in high-T_O Y-Ba-Cu-O systems.更多还原