摘要
本文对不同氧浓度的GdBa_2(Cu_(1-x)Fe_x)_3O_(7-8)系(其中x=0.005—0.01)进行了温度范围从20K到300K的^(57)Fe穆斯堡尔谱分析。处于正交相的谱具有四条四极双线,其中三条来自Cu(1)位,而具有最小四极分裂值的一条来自Cu(2)位。从各谱线相对强度对温度的依赖关系,可得Cu(1)位置上不同区域的德拜温度。织构样品用来分析各四极双线的极化情况。以幻角测量时,可得Cu(1)位的振动各向异性(Goldanskii-Karyagin Effect)。Cu(1)位上最大的四极分裂双线表明其具有最低的德拜温度和最强的振动各向异性。
The GdBa_2 (Cu_(1-x)Fe_x)_3O_(7-δ)system with x=0.005—0.01 and various oxygen concentrations was investigated by ^(57)Fe-Mossbauer spectroscopy in temperature range 20K to 300K. The spectra of the orthorhombic phase were analyzed with four quadrupole doublets. Three of them were attributed to substitutional Cu (1) sites and one (with the smallest quadrupole splitting) to the substitutional Cu (2) site. From an analysis of temperature dependence of the relative site intensities, different local Debye temperature for the Cu (1) sites were derived. Highly texturized absorbers were investigated to study the polarization dependence of the four quadrupole doublets. Measurements at the magic angle gave evidence for a vibrational anisotropy (Goldanskii-Karyagineffect) of the Cu (1) sites. The Cu (1) site with the largest quadrupole splitting exhibited the lowest Debye temperature and the largest vibrational anisotropy.
出处
《高能物理与核物理》
CSCD
北大核心
1993年第11期971-975,共5页
High Energy Physics and Nuclear Physics
