Temperature-dependent x-ray studies of the high-$T_c$ superconductor ${\mathrm{La}}_{1.9}$${\mathrm{Ba}}_{0.1}$${\mathrm{CuO}}_4$

Simultaneous x-ray diffraction and four-probe electrical resistance measurements have been performed as a function of temperature on a polycrystalline sample of the high-$T_c$ material ${\mathrm{La}}_{1.9}$${\mathrm{Ba}}_{0.1}$${\mathrm{CuO}}_4$. Comparisons of the diffraction spectra between 290 and 18 K show no evidence of any gross structural distortions. Least-squares refinements of the tetragonal unit-cell parameters at several temperatures indicate smooth monotonic thermal expansions of about 0.10±0.05% along the a axis and about 0.35±0.10% along the c axis over this temperature range.