Observation of the thermal diffuse scattering inLa2−xMxCuO4(M=Sr,Ba)

Thermal diffuse scattering of ${\mathrm{La}}_{2-x}{M}_x\mathrm{Cu}{\mathrm{O}}_4$ ($M=\mathrm{S}\mathrm{r},\mathrm{B}\mathrm{a}$) is examined by means of electron diffraction, both at room temperature and liquid-nitrogen temperature. The diffraction patterns show nonradial diffuse streaks which correspond to thermal diffuse scattering distributed on ${\mathrm{}\left\{100\right\}\mathrm{}}_t$ and ${\mathrm{}\left\{114\right\}\mathrm{}}_t$ planes in reciprocal space. In addition, strong diffuse scattering along the ${\mathrm{}\left[114\right]\mathrm{}}_t$ and ${\left[11\mathrm{}\overline{4}\right]}_t$ directions around fundamental spots is also observed in the orthorhombic phase.