DAISY: simple simulation of spin dynamics in nanoscale magnets

We present DAISY, a web-based computational tool for the simulation of dynamic magnetic properties of single molecule magnets and supermagnetic nanoparticles. The tool is parametric and accepts relaxation parameters of different mechanisms, including Orbach, Raman, Quantum Tunneling of the Magnetization and the direct relaxation process. The dynamic magnetic response in presence of an oscillating (ac) magnetic field can be simulated, as well as magnetic hysteresis due to a magnetic field sweep between two limits and a simple magnetization relaxation in presence of a static magnetic field. This allows verifying whether the parameters extracted from ac magnetometry or magnetization relaxation are adequate to simulate magnetic hysteresis or other processes have to be considered to properly describe the system of interest. Calculations are inexpensive and typically take a few seconds, whether online or on a local computer, allowing a frugal approach to modelling of magnetic dynamics. We showcase DAISY with a dysprosium bis(amide)–alkene complex which was recently shown to present magnetic hysteresis up to T = 100 K, and find that the parameter sets extracted from ac fits cannot fully reproduce magnetic hysteresis experiments. We offer some paths forward.