First principles understanding of single domain magnetizations—Part I: the single domain comprehensive calculator (SDCC) open source library

SUMMARY The behaviour of uniaxial single domain magnetite particles in rock and paleomagnetic experiments was first described in the 1940s by Néel and Stoner and Wohlfarth. Since this time, micromagnetism has allowed us to gain a better understanding of magnetic particles in the single vortex or multi-domain states. By contrast, when describing the behaviour of assemblages of single domain particles, simplifying assumptions made in the 1940s are still used today. In particular, most rock and paleomagnetic simulations involve magnetite with a uniaxial anisotropy. These assumptions are not necessary in the modern day, as data on other magnetic minerals has been collected, and modern computers are powerful enough to easily calculate the behaviour of multiaxial particles. We present a new software package called the single domain comprehensive calculator (SDCC). This package can simulate a large number of thermally activated rock and paleomagnetic experiments with distributions of single domain particles. These include acquisition of viscous remanence, thermal demagnetization experiments, hysteresis loops and paleointensity protocols. The package provides a simple Python scripting interface for users to define custom experiments and run models on a laptop computer. Preliminary simulations run with the SDCC demonstrate that magnetocrystalline anisotropy can have a significant effect on the thermoviscous behaviour of single domain particles, despite normally being ignored in models. This highlights a need for further investigation into the behaviour of single domain particles.