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The polycrystalline samples of ${\mathrm{Bi}}_{2}{\mathrm{Sr}}_{2}{\mathrm{CaCu}}_{2}{\mathrm{O}}_{y}$ (Bi2212) with different oxygen content, ${\mathrm{Bi}}_{2}{\mathrm{Sr}}_{2}{\mathrm{Ca}}_{1\ensuremath{-}x}{\mathrm{Pr}}_{x}{\mathrm{Cu}}_{2}{\mathrm{O}}_{y}$ and ${\mathrm{Bi}}_{2}{\mathrm{Sr}}_{2\ensuremath{-}x}{\mathrm{La}}_{x}{\mathrm{CaCu}}_{2}{\mathrm{O}}_{y},$ have been characterized by x-ray-diffraction and Raman-scattering measurements. It is found that the $c$-axis parameter decreases with increasing doping concentration (Pr or La) or oxygen content. The softening of the ${O(2)}_{\mathrm{Sr}}{A}_{g}$ mode corresponds to the decrease of the $c$-axis parameter. The effect of Pr substitution for Ca on this mode is smaller than that of La substitution for Sr. The shift of the ${O(1)}_{\mathrm{Cu}} {B}_{1g}$ mode is related to the ionic size of the doping element. The ${O(3)}_{\mathrm{Bi}}{A}_{g}$ mode does not exhibit remarkable frequency shift since the $\mathrm{Bi}\ensuremath{-}O(3)\ensuremath{-}\mathrm{Bi}$ force constant nearly remains unchanged upon doping. The effect of oxygen content on the ${O(2)}_{\mathrm{Sr}}{A}_{g}$ mode in the Bi2212 system is in contrast to that on the corresponding ${O(4)}_{\mathrm{Ba}}{A}_{g}$ mode in the Y123 system. Change in valence is the dominating effect causing the frequency shift of the ${O(2)}_{\mathrm{Sr}} {A}_{g}$ mode.

Transition-metal-doped ${\mathrm{Bi}}_{2}$${\mathrm{Sr}}_{1.8}$${\mathrm{La}}_{0.2}$${\mathrm{Cu}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$${\mathit{M}}_{\mathit{x}}$${\mathrm{O}}_{\mathit{y}}$ (M=Fe, Co, Ni, and Zn) samples were synthesized. X-ray diffraction analysis showed that these 3d elements had different solubility in ${\mathrm{Bi}}_{2}$${\mathrm{Sr}}_{1.8}$${\mathrm{La}}_{0.2}$${\mathrm{CuO}}_{\mathit{y}}$. The limits of solid solution formation were at x=0.5 for the Fe system, x=1.0 for the Co system, and x=0.1 for the Ni and Zn systems. The effect of these 3d metal substitutions for Cu on the incommensurate modulation structure in ${\mathrm{Bi}}_{2}$${\mathrm{Sr}}_{1.8}$${\mathrm{La}}_{0.2}$${\mathrm{CuO}}_{\mathit{y}}$ was examined by means of electron diffraction. The experimental results showed that all the substitutions of Fe, Co, Ni, and Zn for Cu decreased the modulation periodicity. It decreased from 4.32b at x=0 to 3.95b at x=0.5 for the Fe system, 3.82b at x=1.0 for the Co system, 4.24b at x=0.1 for the Ni system, and 4.18b at x=0.1 for the Zn system, respectively. In addition, the structure distortion characteristic related to the change in the incommensurate modulation was examined with Raman scattering. The experimental data showed that the vibration properties of the oxygen atoms in both Bi-O and Sr-O bondings also changed with the decrease in the modulation periodicity. This behavior can be considered a consequence of structural relaxation caused by the enhancement of the degree of crystal misfit. \textcopyright{} 1996 The American Physical Society.