Apparatus for measuring the hysteresis loop of magnetic film
US4922200A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 25, 1989 |
| Grant date | May 1, 1990 |
| Priority date | — |
| Expiry date | Aug 25, 2009 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R33/14
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A magneto-optic Kerr effect hysteresis loop measuring apparatus is provided which employs a pair of pole-pieces of the same magnetic polarity providing a high and uniform magnetic field strength in the gap between the oppositely disposed faces of the pole-pieces. The spot on the product which is to be nondestructively tested is placed in the gap between the pole-pieces in a region of uniform saturating magnetic field. A laser beam having a high polarization ratio is directed along an incident path with a spot on the surface of the product to be nondestructively tested, and a reflected beam is processed in a Kerr effect detector to provide hysteresis loop data. This data is capable of providing information sufficient to determine the squareness of the hysteresis loop and the coercivity of high coercivity material being nondestructively tested.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.