$b$-hadrons decays at ATLAS

Recent results on $\Lambda^0_b$ baryon and $B_c^+$ meson decay studies from the ATLAS experiment at the LHC are presented. These include measurement of the parity-violating asymmetry parameter $\alpha_b$ and the helicity amplitudes for the $\Lambda^0_b\to J/\psi\Lambda^0_b$ decay, first observation of the $\Lambda^0_b\to\psi(2S)\Lambda^0_b$ decay and measurement of its rate relative to the $\Lambda^0_b\to J/\psi\Lambda^0$ decay, and study of the $B_c^+\to J/\psi D_s^{(*)+}$ decay properties.