Some additional parameters to estimate domain state from isothermal magnetization measurements

Domain state and mixing analysis based on isothermal magnetization measurements is often restricted to the use of the Day plot. In order to make more information from simple rock magnetic measurements accessible for the quantitative analysis of domain state, four additional parameters are proposed. Two of them, a hysteresis shape parameter and a coercivity ratio, can be directly calculated from standard measurements of the hysteresis loop and backfield curve. The other two, a transient energy dissipation ratio and the viscosity of isothermal remanent magnetization, require additional measurements, which, however, do not increase measurement time noticeably. The theoretical background of the above parameters is discussed. Their ability to discern domain state is shown for a small set of synthetic magnetite and titanomagnetite samples and in a case study of a transect from the rim to the center of a dredged mid-ocean ridge basalt.