  The mixed spin-(1,1/2) Ising-Heisenberg model on a distorted diamond chain
with the spin-1 nodal atoms and the spin-1/2 interstitial atoms is exactly
solved by the transfer-matrix method. An influence of the geometric spin
frustration and the parallelogram distortion on the ground state,
magnetization, susceptibility and specific heat of the mixed-spin
Ising-Heisenberg distorted diamond chain are investigated in detail. It is
demonstrated that the zero-temperature magnetization curve may involve
intermediate plateaus just at zero and one-half of the saturation
magnetization. The temperature dependence of the specific heat may have up to
three distinct peaks at zero magnetic field and up to four distinct peaks at a
non-zero magnetic field. The origin of multipeak thermal behavior of the
specific heat is comprehensively studied.
