Magnetooptics magnetooptical Kerr effect

Thin films of Cu, Co and Ni on Si were prepared from different aqueous electrolytes containing sulfates of the respective metals as well as some supporting electrolyte/additive. Voltammetry and current transients were used to analyze the electrochemical aspects of the deposition. The electrodeposited layers were investigated by scanning electron microscopy (SEM), Rutherford backscattering (RBS), magnetooptical Kerr effect (MOKE), X-ray diffractometry (XRD) as well as by electrical measurements. 

Magnetism is a central field in condensed matter research, basic as well as applied. Several physical effects such as, for example, the magnetooptic Kerr effect, are caused by the simultaneous occurrence of spin polarization and spin-orbit coupling. It is therefore necessary to include spin polarization in the (fully) relativistic band structure formalisms. Feder et al. 

Kerr observed [165] 125 years ago that linearly polarized light by reflection from a magnetic solid has its polarization plane rotated with respect to that of the incoming light. This magnetooptic Kerr effect (MOKE) is... 

Before MFM measurements all films were characterized using magnetooptical Kerr effect millimagnetometry. That provides remanence, coercivity, and magnetic anisotropy constants. 

Fig. 8. Principle of the magnetooptical read-out of domain patterns by the polar Kerr effect. The polarisation plane of the incoming laser beam is rotated clock- or counterclockwise according to the orientation (up or down) of the magnetic moments.

From the write and read process sketched so far, some requirements for MO media can be derived (/) a high perpendicular, uniaxial magnetic anisotropy K in order to enable readout with the polar Kerr effect (2) a magnetooptically active layer with a sufficient figure of merit R 0K where R is the reflectivity and 0K the Kerr angle (5) a Curie temperature between 400 and 600 K, the lower limit to enable stable domains at room temperature and the upper limit because of the limited laser power for writing. 

The collection presented here is far from being complete. Extended bibliographies including more than 10.000 references on relativistic theory in chemistry and physics have been published by Pekka Pyykko [32-34]. We took much advantage of his careful and patient work when preparing this chapter. Specialized on solid state effects are recent reviews on magnetooptical Kerr spectra [35] and on density functional theory applied to 4f and 5f elements and metallic compounds [24]. 

In addition to the above inductive technologies for information storage, devices based on the Faraday or Kerr effects are being developed. The aim is to increase two of the most appreciated characteristics in storage technology devices data density and access time. The storage capacity of a magnetooptical disc is currently 600 MB (files, 1991). An additional characteristic of these methods is that the wear problem is virtually eliminated. 

Fig. 5.20. Magnetooptical recording technology (a) thermomagnetic writing (b) reading by means of the Kerr effect. (Adapted from Marchant, 1990.)...

---