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Antiferromagnetic spin segments are quantum objects with discrete spectrum of excitations. Here we report the characterization of two molecular derivatives, namely, Cr 6 InNi and Cr 7 InNi, which are odd-and even-membered spin cyclic systems magnetically broken by an In 3+ ion. Analysis of low-temperature specific heat, susceptibility, and magnetization allows us to determine the microscopic parameters of the spin Hamiltonian and the pattern of the spin excitations. It turns out that the exchange coupling and the anisotropy constants in Cr 6 InNi and Cr 7 InNi are quite close to those in Cr 7 Ni-piv. X-ray absorption experiments evidence that the oxidation state of Cr 3+ and Ni 2+ and their local symmetries are essentially the same in the Cr 6 InNi, Cr 7 InNi, and Cr 7 Ni-piv clusters. Thus the main difference resides in the number and topology of spins in the different derivatives. Based on these grounds, we show …
American Physical Society
Publication date: 
25 Jun 2009

A Ghirri, G Lorusso, F Moro, F Troiani, V Corradini, C Muryn, F Tuna, G Timco, REP Winpenny, M Affronte

Biblio References: 
Volume: 79 Issue: 22 Pages: 224430
Physical Review B