| 摘要 |
A magnetometer in which at least two modes of drive are employed in exciting sensor and/or sample so that the sensor provides an output indication of magnetic moment which is a function of both drive modes. The drive modes may be periodic at specific driving frequencies, aperiodic or may comprise a unidirectional portion of a mode. The output of the sensor contains components representative of the frequency or frequencies of the first mode modulated at the frequency or frequencies of the second mode. This sensor output is then analyzed to provide an indication of sample magnetic moment as a function of the frequency components of both modes of drive in order to eliminate contributions to the indicated magnetic moment from background signals or other perturbations which may be present under single mode operation. The multiple mode magnetometer is useful in several embodiments for production line applications, investigations of magnetic properties of inhomogeneous magnetic materials, as well as for general magnetic moment measurements. The concept of a multimode magnetometer also may be extended to include a multiplicity of modes.
|
