Static Spin Correlation in LTT Phase of La$_{1.875}$Ba$_{0.075}$Sr$_{0.05}$CuO$_4$

We have carried out elastic neutron scattering measurements on La$_{1.875}$Ba$_{0.075}$Sr$_{0.05}$CuO$_4$ single crystal ($T_c\approx$10K). Incommensurate elastic magnetic peaks were observed in the low-tamperature tetragonal phase with the propergation vector parallel/perpendicular to in-plane Cu-O bond direction. The magnetic peak intensity normalized by the sample volume is approximately six times larger than that of the orthorhombic La$_{1.88}$Sr$_{0.12}$CuO$_4$ at low temperature.