ISSN:
1089-7550
Quelle:
AIP Digital Archive
Thema:
Physik
Notizen:
Among the techniques for studying magnetic materials, methods utilizing magnetic dichroism in the soft x-ray region are receiving particular attention because of the unique feature of chemical specificity introduced by probing core levels. In soft x-ray absorption of linearly polarized light, the dichroism is proportional to the square of the magnetization M. The transverse magneto-optic Kerr effect is characterized by a change of the specular reflectivity when M is reversed, thus it is linear in M. Due to the relationship between reflected and transmitted radiation, a dichroism may also be expected in the absorption. We confirmed this by quasi-simultaneous measurement of the reflectivity and total yield around the Fe and Co 3p thresholds, using p-polarized light at oblique incidence: Switching the magnetization between the two directions normal on the plane of incidence indeed shows a magnetic dichroism. The relationship between the dichroisms in total yield and specular reflectivity was investigated as function of incidence angle.In addition to this new form of magnetic dichroism, other forms have been explored for imaging near-surface magnetic domains of elemental and compound materials in a total yield microscope. By using different light polarizations different components of the magnetization are detected. p- and circular polarization yield magnetization components parallel to the surface, normal to and in the plane of light incidence, respectively. With linearly s-polarized light, images similar to those with circularly polarized light were obtained. This is evidence for a sizeable Faraday rotation, leading to a significant degree of circular polarization before the optical transition takes place. The helicity of the Faraday-induced ellipitical polarization depends on the local sample magnetization, thereby generating the magnetic contrast in an analogous fashion as does circularly polarized light. This mechanism is expected and found to be effective also for p-polarized light, however, with contrast smaller than that related to the transverse MOKE. Finally, we report first results for an antiferromagnet, where domains were observed via the M-quadratic Voigt effect in the soft x-ray region. © 1996 American Institute of Physics.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1063/1.361985
Permalink
