Garnets anisotropy

Figure 3-5 MnO partition between and diffusion in two minerals, olivine and garnet. Diffusional anisotropy of olivine is ignored. Initially, MnO in both phases were 0.2 wt%. As the two minerals come into contact, there will be diffusion to try to reach the equilibrium state. The partition coefficient (Mn)oiiv/(Mn)gt is assumed to be 0.59. The diffusivity in olivine is assumed to be 10 times that in garnet, resulting in a wider diffusion profile with a smaller slope in olivine.

The development of the bubble domain memory has been remarkable in that since the discovery of the growth induced anisotropy in garnets, problems connected with materials have been relatively few and not too difficult to solve. A major reason is that the different sizes and magnetic properties of the rare earths offer a wide range of choices for the materials designer. 

Geschwind, S. (1961). Paramagnetic resonance of Fe in octahedral and tetrahedral sites in yttrium-gallium garnet (YGaG) and anisotropy of yttrium-iron garnet (YIG). Physical Review, 121, 363-74. 

Gyorgy, E. M., Sturge, M. D., Van Uitert, L. G., Heilner, E. J. Grodkiewicz, W. H. (1973). Growth-induced anisotropy of some mixed rare-earth iron garnets. Journal of Applied Physics, 44, 438-43. 

A = elastic anisotropy a = cubic lattice constant of garnet... 

In epitaxy, there are three major causes of stress in the film. One is the lattice misfit. The other is the mismatch in the thermal expansions. The third cause is the concentration or impurity effect. The last effect is now reintroduced into the garnet film to achieve the increase in its magnetic uniaxial anisotropy. The ion... 

The magnetocrystalline anisotropy is a direct measure of the contributions from individual cations in the lattice. The success of the single ion model of the anisotropy theory (Yoshida and Tachiki, 1957 Wolf, 1957), as applied to the ferrites and garnets, makes the anisotropy constants very useful. 

Whenever multiple types of cations occupy the same crystallographic sites in the garnets, noncubic uniaxial magnetic anisotropy was found to exist. Although... 

Representative noncubic anisotropy results can be shown in the case of the garnet... 

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