Dr. Rudolf Schaefer

Abstract:

Two aspects of magneto-optics are reviewed that have hardly be considered in the past: (i) For Magneto-optical Kerr Effect (MOKE) magnetometry it will be shown that the obtained hysteresis loops need to be interpreted very carefully as they are measured locally, determined by the internal (not applied) magnetic field and by local magnetization processes [1]. MOKE hysteresis loops are therefore in most cases significantly different from integrally measured loops on the same specimen. (ii) For wide-field MOKE microscopy numerous magneto-optical effects will be discussed that lead to intensity-based domain contrasts in the absence of analyser and compensator, which are the main optical components in conventional MOKE microscopy [2]. This includes the Transverse Kerr effect, a novel 45°-dichroic effect (Oppeneer effect), the Magnetic Linear Dichroism effect, and the Dichroic Gradient effect. All these effects require linearly polarized light for illumination. A further effect is the Magnetic Circular Dichroism effect that requires circularly polarised illumination.