Sensor Developments
Films
For sensory applications and optical components, we develop customer-specific single-crystal garnet films. These are based on bismuth substituted rare earth iron garnet with stoichiometry (Bi,RE)3(Fe,Ga)5O12. The garnet films are deposited by liquid phase epitaxy (LPE) on 1 inch (R&D level) and 3 inch (production level) gadolinium gallium substrates (Gd3Ga5O12). Perfect single-crystallinity and low crystal defect density ensure high quality films for optical applications.
Properties
Generally, the already developed magneto-optical sensor types (A to D) have the following properties:
| Specific Faraday rotation: | 1 to 1.5 °/µm |
| Operating temperature range: | 23 ± 8 °C for all types, type C also cryogenic |
| Magnetic dynamic range: | 0.05 bis 140 kA/m |
| Sensor chip sizes: | 8 x 8 mm, 20 x 15 mm (typ.) |
| Local resolution: | 1 to 30 µm (system dependent) |
| Sensor total thickness: | 0.5 mm |
| Transmission range (VIS): | λ > 530 nm |
There are differences in magnetic anisotropy. The sensor types A and D (bias) have an out-of-plane anisotropy. In contrast, types B and C have a predominant in-plane anisotropy.
Sensor design
Depending on the field of application, mirrors with adapted properties are applied to the magneto-optical films and optionally provided with a scratch-resistant layer. Sensor design is essential to achieve a high Faraday effect and the best possible spatial resolution.
Special developments
Due to the complete in-house production of magneto-optical films, we can develop special garnet films according to customer requirements. The following properties, for example, can be realized:
| Film thickness: | 0.5 to 10 µm (typ.) |
| Faraday rotation: | 0.5 to 15 deg (polar) |
| Anisotropies: | Out-of-plane (low and high uniaxial), in-plane |
| Chip sizes: | greater than 3 x 3 mm to a maximum of 60 x 45 mm |
We would be pleased to provide you with further information in response to your enquiry, and to submit an R&D offer with regard to a special development.
