  The paper presents a theoretical study of magnetocaloric properties of
polyoxovanadate molecular magnet V6 containing 6 vanadium ions carrying quantum
spins $S = 1/2$. The characteristic property of such structure is the presence
of two weakly interacting spin triangles with all-antiferromagnetic couplings.
The properties of the system are described using the exact numerical
diagonalization approach applied to the quantum Heisenberg model and utilizing
a field ensemble formalism. The dependence of the magnetic entropy and magnetic
specific heat on the temperature and external magnetic field is calculated and
extensively discussed. The magnetocaloric properties are quantified by
isothermal entropy change and entropy derivative over the magnetic field. An
interesting behaviour of isothermal entropy change is found, with high degree
of tunability of the magnetocaloric effect with the initial and final magnetic
field values.
