The magnetic recording stability of vortex state irregularly shaped natural iron oxides: raw data, processing and micromagnetic modelling results

Magnetic minerals, especially those existing within the vortex domain state, serve as the primary natural archives of ancient magnetic fields. In this investigation, we introduce an innovative method to examine the magnetic stability of remanence-bearing minerals. This method involves integrating Synchrotron-based Ptychographic X-ray Computed Nano-tomography (PXCT) with micromagnetic modelling. PXCT, a tomographic technique, is a non-destructive resource, which enables its application to valuable (unique) samples. When applied to a microscopic sample of weakly magnetic carbonate rock, PXCT revealed numerous nanoscopic grains of magnetite/maghemite, each exhibiting diverse morphologies, alongside various non-magnetic minerals present in the rock matrix. Subsequently, micromagnetic models were employed to predict the properties of these grains and investigate the potential impacts of irregular morphologies.