Spin dynamics in magnetic molecules

Abstract

In this Ph.D. thesis the spin dynamics in several types of magnetic molecules has been investigated by developing models and computational techniques in the framework of the spin Hamiltonian approach. The studied systems are composed by a core of magnetic ions surrounded by shells of organic ligands. Inside each core the different spins strongly interact via superexchange, whereas the interactions between spins of different cores are prevented by the ligands. A deep understanding of the spin dynamics is crucial both for the investigation of fundamental quantum phenomena and for the potential applications. The spin dynamics has been studied both directly - through the analysis of neutron scattering cross sections on the Cr8Zn spin segment - and indirectly - through the analysis of macroscopic measurements, as magnetization and specific heat, in Cr8Cd, Cr7Ni, and Cr8Ni rings. In addition, it has been shown that NMR measurements can provide crucial information about the relaxation dynamics of magnetic molecules, such as the Fe8 nanomagnet, the V12 antiferromagnetic cluster, the Fe30 icosidodecahedral molecule and the Cr7Ni heterometallic ring. In all the studied systems the developed models well capture the main features of the experimental data.