Volume 86, Issue 5, 01 September 1999
Index of content:
- MAGNETISM AND SUPERCONDUCTIVITY (PACS 74-76)
Microstructure, magnetic, and magneto-optical properties of chemical synthesized Co–RE ferrite nanocrystalline films86(1999); http://dx.doi.org/10.1063/1.371117View Description Hide Description
The sol-gel synthesis of Co–RE ferritenanocrystallinefilms was accomplished on monocrystalline silicon substrates, and the influence of RE ions on structure, magnetic, and magneto-optical (MO) properties of the resultant ferrites was examined. The results obtained reveal that, when the ferritefilms have pure spinel phase with slightly enlarged cell constants and lattice distortion due to the large radii of RE ions. The RE ions tend to decrease the room-temperature magnetization as well as the Curie point of products, and may have a certain contribution to coercive force except for a nonmagnetic ion. For the present optical structure in which MO layers are substrated on silica, Co–RE ferritefilms show the peak Kerr rotation at a shorter wavelength than the film, and Er or Tm doped samples exhibit an interesting enhancement of the MO effect.
86(1999); http://dx.doi.org/10.1063/1.371118View Description Hide Description
Granular alloys of Cu with FeCo were prepared by the melt-spinning technique. The alloy was characterized by x-ray,transmission electron microscopy, vibrating sample magnetometer, and magnetoresistancemeasurements. The alloys were heat treated for different temperatures to optimize the magnetoresistanceproperties. Structural characterization reveals that the FeCo phase initially precipitates out as fcc and later transforms to the bcc structure by martensitic transformation. It is seen that the trend in the magnetoresistanceproperties is different for the measurements carried out at room temperature and 4.2 K. This has been attributed to the transformation of fine fcc precipitates to the bcc structure during the low temperature measurements. It is seen that the presence of fine particles causes an increase in the field for saturation and is not suitable for applications where moderate field giant magnetoresistance is required.