System for measuring magnetostriction employing a plurality of external magnetic field rotation harmonics
US6664783B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 15, 2002 |
| Grant date | Dec 16, 2003 |
| Priority date | — |
| Expiry date | Jul 15, 2022 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R33/18
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A system for measuring the magnetostriction coefficient &lgr; of a sample material applied to a substrate element fixed at one end leaving the other end free to be deflected. An external rotating magnetic field of rotation frequency f and intensity Hext is applied to the cantilever substrate element the amplitude Am of the deflection of the free end is measured at each of a plurality of rotation frequency harmonics {fm} by, for example, using a plurality of lock-in amplifiers. The harmonic deflection amplitudes {Am} are combined to determine the magnetostriction coefficient &lgr; of the sample material. At an Hext equal to the sample saturation moment Msat and assuming a 15 Oe sample anisotropy Hk and coupling bias Hp, the error in the saturation magnetostriction coefficient &lgr;S measured according to this invention may be reduced by 80% to 90% over the error seen when using only the second harmonic deflection amplitudes A2.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.