Simple models and powerful tools for seeking a comprehensive understanding of the magnetic properties of molecular magnets.

The Heisenberg model provides a simple but powerful theoretical platform for modelling magnetic molecules. In this article, we demonstrate that--despite its simplicity--an isotropic Heisenberg model successfully provides a comprehensive description of the magnetic properties of the {Fe₈}-cubane and the {Cr₁₂Cu₂} magnetic molecules. However, in order to achieve this success, it is necessary to employ a variety of sophisticated experimental and theoretical techniques. These include the use of pulsed-field measurements to observe a high-field (41 T) ground-state level crossing in the {Fe₈}-cubane system, and tunnel-diode oscillator measurements, which we use to observe excited-state level crossings in the {Cr₁₂Cu₂} ring. For these two systems, the theoretical modelling was carried out using matrix diagonalization and quantum Monte Carlo calculations, respectively.