Skip to main content Accessibility help
×
Home

Application of Magnetic Garnet Films for Magnetooptical Imaging of Magnetic Field Distributions

  • H. Dötsch (a1), C. Holthaus (a1), A. Trifonov (a1), M. Klank (a1), O. Hagedorn (a1), M. Shamonin (a2) and J. Schützmann (a3)...

Abstract

Rare-earth iron garnet films of high quality can be grown by liquid phase epitaxy on paramagnetic substrates of gadolinium galliumgarnet. Such films are currently used for imaging of the spatial distribution of magnetic fields. This application is based on the Faraday rotation which can strongly be enhanced by bismuth incorporation.

The physical properties of the films can be controlled by the chemical composition, the growth conditions and the crystallographic orientation. The sensor properties like sensitivity, dynamic range, signal linearity and unambiguity must be optimized according to the application desired. These properties, however, are not independent of each other. In addition, they strongly depend on the optical wavelength. Thus, it is necessary to find compromises.

The influence of Faraday rotation, Faraday ellipticity, optical absorption, magnetic anisotropies and film thickness on the performance of a magnetooptical indicator film is investigated. Based on the swing of the photoresponse, a new optimization process is introduced. The process is experimentally verified and application examples are demonstrated.

Furthermore, two methods are presented to enhance the sensitivity of magnetooptical sensors. Using specific crystallographic orientations, an easy plane of magnetization can be induced which is inclined with respect to the film plane. If the magnetization lies in this plane a very high sensitivity is achieved. The dependence of the geometrical orientation of the easy plane on the growth direction is calculated and the sensitivity and dynamic range are derived. Experimental results of a [112] oriented garnet film are in good agreement with calculations.

Garnet films which are magnetized along the film normal due to a strong induced uniaxial anisotropy support magnetic domains. If the collapse field perpendicular to the film plane is small, such films can be used as very sensitive indicator films. Such films are easier to prepare than sensitive in-plane films. However, the spatial resolution is limited by the size of the domains. This disadvantage can be avoided by applying a bias field in the film plane. Directly at the in-plane collapse field the sensor film is in-plane magnetized yielding high spatial resolution at still high sensitivity. The variation of magnetooptical images with in-plane induction is demonstrated. Experimental results are in agreement with calculations.

Copyright

References

Hide All
1. Magneto-Optical Imaging, ed. Johansen, T. H. and Shantsev, D. V.. NATO Science Series, II. Mathematics, Physics and Chemistry 142, Kluwer Academic Publishers (2004).
2. Shamonin, M., Beuker, T., Rosen, P., Klank, M., Hagedorn, O. and Dötsch, H., NDT & E International 33, 547 (2000).
3. Shamonin, M., Klank, M., Hagedorn, O. and Dötsch, H., Appl. Optics 40, 3182 (2001).
4. Fitzpatrick, G. L., Thome, D. K., Skaugset, R. L., Shih, E. Y. C., and Shih, W. C. L., Mater. Eval. 51, 1402 (1993):
5. Fratello, V. J., Slusky, S. E. G., Brandl, C. D. and Norelli, M. P., J. Appl. Phys. 60, 2488 (1986).
6. Hansen, P., Clages, C. P. and Witter, K., J. Appl. Phys. 60, 721 (1986).
7. Syvorotka, I. M., Ubizskii, S. B., Kucera, M., Kuhn, M., and Vertesy, Z., J. Phys D, Appl. Phys. 34, 1178 (2001).
8. Klank, M., Hagedorn, O., Holthaus, C., Shamonin, M. and Dötsch, H., NDT & E International 36, 375 (2003).
9. Klank, M., Hagedorn, O., Shamonin, M. and Dötsch, H., J. Appl. Phys. 92, 6484 (2002).
10. Holthaus, C., Trifonov, A., Dötsch, H. and Schützmann, J., NDT & E International, in press.

Application of Magnetic Garnet Films for Magnetooptical Imaging of Magnetic Field Distributions

  • H. Dötsch (a1), C. Holthaus (a1), A. Trifonov (a1), M. Klank (a1), O. Hagedorn (a1), M. Shamonin (a2) and J. Schützmann (a3)...

Metrics

Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed