Magnetocaloric properties of frustrated tetrahedra-based spin nanoclusters

Highlights: • We study several frustrated Ising nanoclusters with tetrahedra-based topologies. • Ground-state magnetizations and entropies in a field are exactly determined. • In each cluster enhanced magnetocaloric effect is observed near critical fields. • Best magnetocaloric properties shows the cluster of two corner-sharing tetrahedra. -- Abstract: Magnetization, entropy and magnetocaloric properties of various geometrically frustrated tetrahedra-based Ising antiferromagnetic nanoclusters with corner-, edge-, and face-sharing topologies are studied by exact enumeration. It is found that the studied properties strongly depend on the nanocluster topology and can be very different from those of a single tetrahedron as well as the pyrochlore lattice formed by an infinite number of corner-sharing tetrahedra. From the magnetocaloric point of view an important difference from the latter two systems is the absence of the ground-state zero-magnetization plateau in most of the studied structures, which at low temperatures facilitates emergence of a giant magnetocaloric effect in a vanishing magnetic field in the adiabatic demagnetization process. Magnetic systems with such properties might be suitable candidates for technological application as efficient refrigerators to ultra-low temperatures.