<p>Taenite, an iron-nickel alloy with 20-40 at% nickel, is a major constituent of iron meteorites that have been used to infer planetary core compositions. Many aspects of its magnetic properties are controversial, particularly near the Invar (&#8220;invariable&#8221;) composition around 36 at% nickel. Open questions include the conditions under which magnetism is lost, so to address this particular controversy, we undertook a combined magnetic remanence and M&#246;ssbauer study of synthetic taenite at high pressure. We synthesised polycrystalline iron-nickel alloy with 38 at% nickel, loaded the sample into a diamond anvil cell and collected M&#246;ssbauer spectra during decompression from 20 GPa. Our results show a clear loss of magnetism, but at pressures that differ considerably depending on the fitting model. The pressure obtained using the traditional approach involving a magnetic field distribution conflicts with results obtained from other methods, while a simple model based on magnetic field fluctuations gives results that are consistent with other data. Comparison of data from all methods provides insight that can be applied to planetary magnetism.</p>
Sensing Mechanism of Surface Acoustic Wave Magnetic Field Sensors Based on Ferromagnetic Films