【摘要】 利用飞秒脉冲激光与泵浦－探测技术测量了ＹＢａ＿２Ｃｕ＿３Ｏ＿（７－δ）（其中δ＝０．０，０．１，０．４，０．８）外延薄膜的瞬态反射率改变随时间变化曲线。由于氧含量的不同使得样品瞬态反射率改变随时间变化曲线有很大差异。瞬态反射率改变随时间变化的曲线符号变化可以理解为氧含量的变化改变了样品费密面附近的能带结构。对实验数据的拟合表明δ＝．４　的样品电声子耦合远弱于高Ｔ＿ｃδ＝０的样品。更多还原

【Abstract】 The femtosecond pulsed laser and pump-probe method have been used to mEASU-re the transient change of reflectivity of YBa₂Cu₃O_7-δ（δ=0.0,0.1,0.4 and 0.8）thin films. From the experimental curves the transient changes are found to be very different for samples with different oxygen content.The sign of the changes can bereversed as decreasing the oxygen content.It may be attributed to the changes ofenergy band structure near the Fermi level.After fitting the experimental data,wereveal that the electron-phonon coupling in the sample of=0.4 is much weakerthan high T_c（δ=0.0） sample.更多还原