  The ground state and thermodynamics of a generalized spin-1/2
Ising-Heisenberg diamond chain with the second-neighbor interaction between
nodal spins are calculated exactly using the mapping method based on the
decoration-iteration transformation. Rigorous results for the magnetization,
susceptibility, and heat capacity are investigated in dependence on temperature
and magnetic field for the frustrated diamond spin chain with the
antiferromagnetic Ising and Heisenberg interactions. It is demonstrated that
the second-neighbor interaction between nodal spins gives rise to a greater
diversity of low-temperature magnetization curves, which may include an
intermediate plateau at two-third of the saturation magnetization related to
the classical ferrimagnetic (up-up-up-down-up-up-...) ground state with
translationally broken symmetry besides an intermediate one-third magnetization
plateau reflecting the translationally invariant quantum ferrimagnetic
(monomer-dimer) spin arrangement.
