In Earth sciences, the measurement most commonly used to characterize the magnetic properties of rock specimens for paleomagnetic and paleointensity research is that of a hysteresis loop, M(H), and for many scientists, a vibrating sample magnetometer (VSM) is the system employed for hysteresis loop determinations. A number of parameters can be extracted from the hysteresis loop using a VSM, and now to aid in visualizing data obtained from such measurements, a new software package named Hysteresis Loop Analysis Box (HystLab) has been made freely available for download.
This MATLAB software, developed by the University of Liverpool’s Greig Paterson in collaboration with the Australian National University’s Xiang Zhao and David Heslop and the University of Minnesota’s Mike Jackson, incorporates a number of methods to more efficiently process and more accurately analyze hysteresis loop data. In the related published paper, Paterson discusses guidelines for optimizing the magnetic hysteresis data measurement, noting that they were developed mainly for MicroMag™ 3900 VSMs (previously available from Lake Shore) because “these are the most widely used instruments in the rock magnetic community and are the ones with which we have the most experience.” That said, HystLab can also be used in conjunction with Lake Shore’s 7400 Series VSMs and 8600 Series VSMs.
Also worth noting, according to Paterson, the strategies outlined are also valid for other types of data measured on the same equipment, including isothermal remanent acquisition curves and first order reversal curves (FORCs). FORCs, in particular, can be quite useful for determining the composition of magnetic minerals in rock specimens, especially when trying to differentiate magnetic properties of all particles in a sample.