铁离子在Tl系1223超导相中的分布研究

The Distribution of Iron Ions in Tl-system 1223 Phase Superconductor

对不同掺铁量的Tl系 12 2 3相样品 ,测量了室温和 77K的穆斯堡尔谱 .根据铁可能具有的不同局域环境 ,按四套四极劈裂双峰进行拟合 .发现室温下四套亚谱的同质异能移位均为 0 .2 5mm/s左右 ,表明铁在12 2 3超导相中以高自旋Fe3 + 形式存在 .其四极劈裂分别为 1.40mm/s ,1.12mm/s ,0 .5 5mm/s和 1.90mm/s左右 .按照点电荷 有效价键模型 ,计算了铁处于不同局域位置时的核四极劈裂的大小 .对铁所占晶位进行指认 .

Fe Mossbauer measurements are made by the use of the samples of Tl system 1223 phase superconductors with nominal composition (Tl 0.5 Pb 0.5 )(Sr 0.8 Ba 0.2 ) 2Ca 2(Cu 1- x Fe x ) 3O y (x =0.01, 0.02 , 0.03) at the room temperature. The spectra are deconvoluted into four quadrupole doublets with quadrupole splitting about 1.40?mm/s, 1.12?mm/s, 0.55?mm/s, 1.90?mm/s respectively. This implies that the Fe 3+ occupies the different local lattice sites. By using the point charge effective valence model, the electric gradient (EFG) of different Fe localized sites are calculated, and the Fe 3+ site assignment is proposed.