  Ground-state and finite-temperature properties of the mixed spin-1/2 and
spin-S Ising-Heisenberg diamond chains are examined within an exact analytical
approach based on the generalized decoration-iteration map. A particular
emphasis is laid on the investigation of the effect of geometric frustration,
which is generated by the competition between Heisenberg- and Ising-type
exchange interactions. It is found that an interplay between the geometric
frustration and quantum effects gives rise to several quantum ground states
with entangled spin states in addition to some semi-classically ordered ones.
Among the most interesting results to emerge from our study one could mention a
rigorous evidence for quantized plateux in magnetization curves, an appearance
of the round minimum in the thermal dependence of susceptibility times
temperature data, double-peak zero-field specific heat curves, or an enhanced
magnetocaloric effect when the frustration comes into play. The triple-peak
specific heat curve is also detected when applying small external field to the
system driven by the frustration into the disordered state.
