Rare-earth garnets

D. B. Sirdeshmukh, L. Sirdeshumkh, K. G. Subhadra, K. Kishan Rao, S. Bal Laxman, Systematic Hardness Measurements on Some Rare Earth Garnet Crystals, Bull. Mater. Science, 24,469 (2001). 

In the cases of NiFe204 and the rare earth garnets for microwave use, in which the losses due to conductivity must be minimized, an oxygen atmosphere may be required for sintering so that the concentration of Fe2+ ions is reduced to a very low level. 

Soft magnets Transformer cores [(Zn, M)Fe203, with M = Mn, Co, Mg] magnetic tapes (rare-earth garnets)... 

The magnetic field at Eu + ions measured by the 103-keV resonance in rare-earth garnets doped with 2-5% Sm (M3FesOi2, M = Gd, Tb, Dy, Ho, Er, Eu, Tm, Yb, Lu, Y) increases by only 8% in that order [68]. Identical fields in YIG and LuIG in which the rare earth is diamagnetic show that the rare-earth-iron exchange interaction is insensitive to the lattice parameters which differ by 1%. However, in the series as a whole, the Eu - -/rare-earth exchange interaction does alter and the field shows a linear dependence with the spin moment of the host, = (gj — ). As already seen for the... 

Rare-earth cations usually enter the large dodecahedral sites due simply to their cation radius. The lattice constants of rare-earth garnets are presented in Table 2.5. In addition to the rare earths listed in Table 2.5, Nd3+ Pr3+ cg3+ gj3+ ca2+ La3+, Mn, Na+, Sr +, Pb + and Fe enter c sites, at least as a partial substitution. 

Heilner, E. J. Grodkiewicz, W. H. (1973). Compositional dependence of cubic and uniaxial anisotropies in some mixed rare-earth garnets. Journal of Applied Physics, 44, 4218-19. 

Ostorero, J., Le Gall, H., Makram, H. Escorne, M. (1985). The influence of quenching temperature on the magnetic properties of rare-earth garnet HoIG A1 single crystals. In Advances in Ceramics Fourth International Conference on Ferrites, Vol. 15. Ed. F. F. Y. Wang. American Ceramic Society, Ohio, pp. 265-73. 

Substrates are non-magnetic solid solutions of rare-earth garnets with Ca ", Mg " and Zr " ions. By varying the composition, almost any lattice parameter in the range 12.290-12.620 A can be obtained (Mateika, Laurien Rusche, 1982). 

Fig. 4.23. Saturation magnetisation (in Bohr magnetons per formula unit) as a function of temperature, for rare-earth garnets RFe50,2, where R = Gd, Tb, Dy, Ho, Er, Yb and Y. (Adapted from Moulson Herbert, 1990.)...

Magnetooptical properties of rare-earth garnets have been extensively studied because these ferrites can be prepared as single-crystal films and... 

Mixed oxides with the general formula A3B2X30,2, with body-centred cubic structure. Yttrium and rare earth garnets are ferrimagnetic materials, (q.v.) of which yttrium iron garnet (q.v.) is the most important. 

Representative hyperfine interaction studies (NMR and NGR) of rare earth garnets... 

Theory of ferromagnetic resonance in rare earth garnets II. (Lines with (with C. Kittel and A.M. Portis), Phvs. Rev.. 116. 323 0959). 

The local symmetry distortion model (Akselrad and Callen, 1971) is based on the distortion of the local symmetry around the tetrahedral d-site, caused by referential ordering among their tetrahedral (or other) neighbors. This model is especially useful when the rare earth-based mechanism cannot be operative. In mixed rare earth garnets, a distortion of tetrahedral symmetry can be caused by ordering of dodecahedral site ions. This local symmetry distortion is the cause of noncubic anis otropy. 

All of the rare earth garnets have a set of three bands in the 800-600 cm" region. These bands are isolated by a high-transmission maximum from other... 

The yttrium garnets have a number of distinctive features that set them apart from the rest of the rare earth garnets in each series. The frequencies for YAG at 378, 332, 292, 220 cm" are higher than the other frequencies in the RAG series (table 29.18). In the low frequency region the 93 cm" band is missing from the... 

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