YBa_2Cu_3O_(6+δ)的高频模及其随氧含量δ的变化  

HIGH FREQUENCY MODES OF YBa_2 Cu_3O_(6+5) AND ITS VARLATIONS WITH OXYGEN CONTENT

作　　者：阮景辉[1] 牛世文[1] 成之绪[1] 程玉芬 曾祥欣[1] 勾成[1] 王军[1] 郭立平[1] 林军[1] 俞安孙 沈志功 张泮霖[2] 柴璋 

机构地区：[1]中国原子能科学研究院,北京102413 [2]中国科学院物理研究所,北京100080 [3]中国科学技术大学研究生院,北京100039

出　　处：《物理学报》1993年第7期1121-1126,共6页Acta Physica Sinica

基　　金：国家自然科学基金资助的课题

摘　　要：在中国原子能科学研究院新建的宽角(～30°)Be过滤探测器中子非弹性散射谱仪上,在入射中子能量从10直至150meV的范围内,测量了几种不同氧含量的YBa_2Cu_3O_(6+δ)样品的中子非弹性散射能谱。结果表明:(1)在δ=0和0.2时,在60至150meV能量范围内,发现有强的高频模存在,当其温度高到Nel点(～410K)以上直至466K时,没有观察出高频模强度的减弱。而δ=0.78和0.97时,在75至150meV能量范围内,散射强度在测量误差内为一常数本底,高频模消失。(2)从10直至150meV能量范围内,δ=0.2样品的散射强度反常的强,约为δ=0.78和δ=0.97的散射强度的2至3倍。高频模以及散射强度的巨大差异可归结于反铁磁自旋激发的结果。(3)在60meV以下能量区存在若干分辨清晰的散射峰,其峰位几乎不随δ而变化,这些峰除了包含了Renker和Parshin的结果外,还有若干峰为本文分辨出来的。Inelastic neutron scattering spectra of YBa2Cu3O(6+δ) sample with several different oxygen contents δ have been obtained in the energy range from 10 to 150 meV at a new wide angle (~30°) Be-filter detecter spectrometer, CIAE,Beijing. The experiments show that :(l)For samples with δ=0 and δ=0.2, some strong high frequency modes appear in the energy range from ~60 to ~150 meV,and the intensity of modes does not decrease as the temperature is above Neel point until 466K. For samples with δ=0.78 and 0.97, however, the high frequency modes are not present and the scattering intensity spetra in the energe range from 70 to 150 meV seem to be a featureless background. (2)In the measured energe range from 10 to 150 meV the scattering intensities of sample with δ=0 and 0.2 is about two to three times as that of sample with δ = 0.78 and 0.97. (3) In the energe range below 60 meV, there are many distinct scattering peaks which are almost not shifted with δ, most of peaks are in a-greement with results of Renker and Parshin, and other peaks are observed for the first time. The strong dependence of high frequency modes and scattering intensities on the oxygen content δ would attribute to antiferromagnetics spin wave excitation.

关 键 词：超导体 YBCO 高频模 氧含量 散射 

分 类 号：O511.1[理学—低温物理]