Abstract: Method and sensor for obtaining comparative measurements of hysteresis loss in a ferromagnetic sample. A permanent magnet, polarized normal to the sample surface, is positioned on one side of the surface and is movable along a line of travel between motion limits. A field sensor is mounted in fixed spatial relation on the opposite side of the sample surface at the center of the line of travel. The magnet is moved in forward and reverse directions between the motion limits. The longitudinal magnetic field intensity and the coincidental magnet to field sensor longitudinal distance are sensed at a plurality of distances along the forward and reverse line of travel. For each distance, the difference, D(x), between forward and reverse magnetic fields is calculated and plotted against distance for determining the comparative hysteresis of the sample.

Abstract: Method and sensor for obtaining comparative measurements of hysteresis loss in a ferromagnetic sample. A permanent magnet, polarized normal to the sample surface, is positioned on one side of the surface and is movable along a line of travel between motion limits. A field sensor is mounted in fixed spatial relation on the opposite side of the sample surface at the center of the line of travel. The magnet is moved in forward and reverse directions between the motion limits. The longitudinal magnetic field intensity and the coincidental magnet to field sensor longitudinal distance are sensed at a plurality of distances along the forward and reverse line of travel. For each distance, the difference, D(x), between forward and reverse magnetic fields is calculated and plotted against distance for determining the comparative hysteresis of the sample.

Abstract: Sensors for outputting signals indicative of a magnetic drag force between a ferromagnetic sample that is or has been in motion relative to one or more measurement magnets are described. Such sensors include at least one measurement magnet and a sensing element operably associated therewith, such that upon or after exposure of the measurement magnet(s) to a ferromagnetic sample in motion relative thereto, the sensor can sense the drag force, if any, or changes therein, experienced by the measurement magnet. Devices for detecting and/or measuring magnetic drag force that employ one or more of these sensors are also described, as are various applications for such devices.