Uniaxial magnetism

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 magnetoopticady active layer with a sufficient figure of merit R 0- where R is the reflectivity and the Kerr angle (T) 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. 

Figure 8.9 TbPc2-based single ion magnets (SIMs) [90] (a) Schematic representation molecular localization of the three spin-systems characteristics of the [TbPc2]° complex J = 6, the uniaxial magnetic moment of the 4f configuration / = 3/2 nuclear spin of the only stable and naturally occurring 159Tb isotope S = 1/2 organic radical delocalized over the two Pc ligands. The radical...

Note also that, when a contribution due to a uniaxial magnetic anisotropy is included in the particle energy [see Eq. (4.73)], the emerging parameter h, on changing, in a natural way guides the system through the variety of oscillation situations from the absence of any symmetric potential (an isotropic particle) to a twin pair of infinitely deep wells (a magnetically hard particle). In still other... 

Figures 1 and 2 show the isotherms obtained from the magnetization measurements at different temperatures for TbFeeCosTi and its hydride, respectively. Unlike TbFenTi, the TbFeeCosTi single crystal exhibits a uniaxial magnetic anisotropy over the entire studied range of temperatures from 4.2 K to Tc. It is show that Fe replacement by Co suppresses easy plane anisotropy completely at Co concentration x = 5.

Fig.37 FEM calculation of the deformation of a ferrogel block in a uniaxial magnetic field at different field intensities. The magnetic field strength has a Gaussian distribution along the block as shown in the figure. The position of the field maximum is indicated by arrows...

No single crystals could be manufactured due to principal difficulties (the compound is formed by a peritectoid solid-state reaction which prevents a growth from the melt). The discrepancy between the bulk spontaneous moment [(0.4-0.45))iB/U] obtained for polycrystalline samples at 4.2 K, and the microscopic moment (0.8/xB) derived from neutron diffraction (Frings and Franse 1985a) point to a high uniaxial magnetic anisotropy. This may account for the lack of saturation of the magnetic isotherms in fields up to 35 T. 

Ferguson, E. T. (1958). Uniaxial magnetic anisotropy induced in Fe-Ni alloys by magnetic anneal. Journal of Applied Physics, 29, 252-3. 

The uniaxial magnetic anisotropy. The explanation of the origin of this parameter is still the subject of numerous polemics and discussions. Various models have been advanced in order to determine the origin ... 

Another procedure, such as Mossbauer effect measurements, has been used to determine the magnetic properties. Heiman and Lee (1975) presented a Mossbauer spectrum at 300 K for a Gd23Fc77 film prepared by evaporation and which exhibited a uniaxial magnetic anisotropy. The spectrum differs in shape and in... 

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