Magnetic praseodymium

The valences of the rare-earth metals are calculated from their magnetic properties, as reported by Klemm and Bommer.14 It is from the fine work of these investigators that the lattice constants of the rare-earth metals have in the main been taken. The metals lutecium and ytterbium have only a very small paramagnetism, indicating a completed 4/ subshell and hence the valences 3 and 2, respectively (with not over 3% of trivalent ytterbium present in the metal). The observed paramagnetism of cerium at room temperature corresponds to about 20% Ce4+ and 80% Ce3+, that of praseodymium and that of neodymium to about 10% of the quadripositive ion in each case, and that of samarium to about 20% of the bipositive ion in equilibrium with the tripositive ion. 

Important is the use of light rare earth elonents for production of hard magnetic materials. Most prominent are alloys of samarium with cobalt in the atomic ratio 1 5 or 2 17. It may also be assumed that in further development of these materials on a larger scale that praseodymium, neodymium, lanthanum and also individual heavy rare ecu h elements will be used to achieve particular effects. Interesting is the development of magnetic bubble memories based on gadolinium-galliiimrgarnets. 

Permanent magnets having properties several times superior to any other known materials were developed in 1967. Praseodymium, yttrium, samarium, lanthanum, and cerium are alloyed with cobalt in the range... 

In most of these systems there is clear evidence for the formation of the reduced ion For example, in NdX2 salts this is on the basis of magnetic studies (3J), and with the praseodymium chloride and bromide phases, from qualitative resistivity measurements and their structural relationships to the neodymium chlorides according to x-ray data. Cryo-scopic data for all the systems listed are also consistent with the formation of a as opposed to solute in dilute solution in MX3 (3, 7). 

The lutetium hahdes (except the fluoride), together with the nitrates, perchlorates, and acetates, are soluble in water. The hydroxide oxide, carbonate, oxalate, and phosphate compotmds are insoluble. Lutetium compounds are all colorless in the solid state and in solution. Due to its closed electronic configuration (4f " ), lutetium has no absorption bands and does not emit radiation. For these reasons it does not have any magnetic or optical importance, see also Cerium Dysprosium Erbium Europium Gadolinium Holmium Lanthanum Neodymium Praseodymium Promethium Samarium Terbium Ytterbium. 

It can be seen from the comparison of the known Neel temperatures between R2C3 and RC2 (Atoji 1978) that in the light rare earth compounds the crystal field effect is often predominant, as exemplified by the fact that praseodymium carbides have exceptionally low values of and strongly suppressed ordered moments (1.14/1b in PrC2). In the heavy lanthanide compounds, the exchange interaction and anisotropy energy become the major factors in the magnetization. 

HoBa2Cu 02. By now it is clear that praseodymium is the rare earth most likely to be involved in singlet ground state magnetism, and that pSR can be difficult to understand in that case. The other integer-spin trivalent rare earths... 

Shimoda et al. (1988) succeeded in preparing cast Pr2Fei4B magnets. The anisotropy of these cast Pr-Fe-B magnets can be enhanced by hot-working, in which the deformation comes from the rotation of the Pr-Fe-B-phase grains, which are pulverized during deformation, in a praseodymium-rich liquid phase under pressure (Yuri and Ohki 1994), The mechanism is different from ordinary plastic deformation of metals which is caused by the appearance of dislocations in microstructure. 

Face-centered cubic ( fee) phase cerium, 278-280 gadolinium, 296-297 lanthanum, 277 praseodymium, 281 promethium, 287 ytterbium, 313-314 First-order phase transition, 19-20 Fluorescent lamp wastes recycling, 189/, 191/ Flux/slag process, magnets separation glass slag method, 181—182 by molten fluorides, 181/ plant waste (sludge), 182 rare-earth oxides, 181... 

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