We report the magnetic properties of a new class of materials: Ni9Te6n+ with n = 0, 1, 2. These cluster compounds, which can be charged by chemical means from neutral to 2 +, provide a unique and novel way to change the Fermi level. For most charge states, we observe quenching of the spin and orbital moments at low temperatures, accompanied by a large value for the temperature-independent susceptibility of the ground state. The magnitude and universality of these results among different charge states can be explained neither by local moments in a finite size system nor by the molecular orbital approximation. The generic presence of low-energy magnetic excitations in these compounds indicates that these systems exhibit strong electron correlations and form mesoscopic analogues of the mixed valence/heavy fermion compounds.
Palstra, T. T. M., STEIGERWALD, ML., RAMIREZ, AP., & ZAANEN, J. (1994). Electron correlations in transition metal-telluride cluster compounds. Physica B, 199-200, 619-621. https://doi.org/10.1016/0921-4526(94)91924-0