Dysprosium magnetic field

Dysprosium ethyl sulphate [Dy(C2HsS04)3.9H20, or DyES] is unusual in that it shows a paramagnetic hyperfine interaction considerably less than that of the free ion (Table 17.8) [111]. Single-crystal measurements confirm that the magnetic field coincides with the crystal c axis and is collinear with the... 

As work progressed they found that dysprosium additions to the TbFe2 compound would allow one to use lower magnetic fields to produce the strain with some degradation in the total strain achieved. The optimum composition chosen was Tbo.3Dyo,7Fei 9 and is now known as terfenol-D . 

Mallick, B., Balke, B., Felser, C. and Mudring, A.V, Dysprosium room-tenperature ionic liquids with strong luminescence and response to magnetic fields, Angew. Chem. Int. Ed. 47, 7635-7638 (2008). 

Fig. 26. Magnetic phase diagram of dysprosium obtained from elastic constant C33 measurements in a magnetic field (Isci and Palmer 1978). Ferromagnetic (FM), paramagnetic (PM), helical antiferromagnetic (HAFM) and fan phases are shown.

Giant field dependence of the low temperature relaxation of the magnetization in a dysprosium(III)-DOTA complex. Chem. Commun., 47, 3751-3753 (b) Cucinotta, G., Perfetti, M., Luzon,... 

In early studies, Sagawa et al. (1984a,b) already pointed out the effects of additives such as Co and Dy on improvements of the magnetic properties, especially the Curie temperature (Tc) and coercivity (Hcj), respectively, of Nd-Fe-B sintered magnets. Dy addition increases the intrinsic anisotropy field, which results in an increase of coercivity. The disadvantage of Dy addition, however, is the high cost of dysprosium. 

Two other hydroxides, those of dysprosium and holmium, also order ferro-magnetically, with 7,- = 3.48(1)K and 2.54(1)K, respectively (Catanese and Meissner 1973). The interactions are again mainly dipolar and Ising in nature. The ground states are an almost pure Jz= for Dy, with close to 20, and a non-Kramers doublet with = 15.3 for Ho ". In each case the value of g normal to the c-axis is zero, and the presence of other low-lying crystal-field levels influences the properties above 4K. 

Fig. 6.4. The relative magnetization of dysprosium, as measured by Graham et al. (1973) for various fields in the easy (a) and hard (f>) directions.

Fig. 6.5. The magnetization of dysprosium as a function of applied field (after Feron et al. 1970).

As a typical white light-emission ion, trivalent dysprosium GDy " ) ion generally has two dominant emission bands in the 460-500-nm blue regions and the 560-600-nm yellow regions. The emission has a whitish color that turns to yellow in host lattices where hypersensitivity is pronounced. The former is assigned to the " F9/2 Hi5/2 magnetic dipole transition, which is barely varies with the local symmetry in the crystal field whereas the latter is attributed to the hypersensitive electric dipole transition " F9/2 = 2, AJ = 2) where its intensity is... 

Fig. 14.128. The variation of the ordering temperature and critical field with composition of Dy-Co compounds. The magnetization at 160 kOe is given as a rough indication of anisotropy effects. Elemental dysprosium is shown in the form of filled squares with the ordering tempera ture normalized to the Tc curve (Taylor and Primavesi, 1972a).

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