Aspects of this disclosure relate to one or more particles that move within a container in response to a magnetic field. A measurement circuit is configured to output an indication of the magnetic field based on position of the one or more particles.

To reduce a measurement time, an inspection device includes a stage configured to fix a magnetoresistive random access memory (MRAM) to a stage surface and moving the MRAM, a plurality of magnets configured to generate a gradient magnetic, a plurality of line sensors comprising a first line sensor for detecting a magneto-optical effect at a first location of the MRAM and a second line sensor for detecting the magneto-optical effect at a second location that is different from the first location by moving a location of the MRAM within the gradient magnetic field, and an information processor configured to process the magneto-optical effect detected by the plurality of line sensors. Thus, throughput may be improved.

The disclosure concerns a method for characterizing a magnetic device including a plurality of binary nanomagnets, having the steps of: (i) providing a magnetic device having one or more carriers on or in which the plurality of nanomagnets is arranged or embedded, (ii) applying a saturation magnetic field (.sub.0H.sub.sat) having a first direction to a plurality of binary nanomagnets, (iii) applying a second magnetic field (.sub.0H.sub.c) having a second direction to the plurality of nanomagnets, repeating steps (ii) to (iii), determining a first fraction or percentage () and a second fraction or percentage (.sub.1) of nanomagnets which switched orientation in step (iii) and repeated step (iii) respectively, determining a statistical double-switching percentage .sub.ideal based on the determined first and second fractions or percentages and .sub.1, and determining the effective double-switching fraction or percentage () of individual nanomagnets which switched orientation in step (iii) and in the repeated step (iii).