Samarium magnetic structure

Fomina, LG, Kiskin, M.A., Martynov, A.G, Aleksandrov, GG, Dobrokhotova, Z.V., Gorbimova, Y.G et al. (2004) Lanthanum(III), samarium(III), europium(lll), and thuUum(lll) binuclear acetates and pivalates synthesis, structure, magnetic properties, and solid-phase thermolysis. Zhurrml NeorganJcheskoi Khimii, 49 (9), 1463-1474. 

Figure 9.17 Plot of the in-phase and out-of-phase AC magnetic susceptibility for the complex [SmFe] at driving frequency of 199 Hz and 355 Hz [98]. (Reprinted with permission from B. Yan, and Z. Chen, Cyano-bridged aqua(A, Al-dimethylacetamide)(cyanoiron)lanthanides from samarium, gadolinium, or holmium nitrate and potassium hexacyanoferrate crystal structures and magnetochemistry, Helvetica Chimica Acta, 2001, 84, 817-829 (Figure 7). Wiley-VCH Verlag GmbH Co. KGaA.)...

Four binuclear samarium complexes [Sm( x-p-XOBz)2(Tp)]2 have been prepared by the reaction of SmCl3, K(Tp), and sodium p-X-benzoate (X = H, Cl, F, NO2) in 1 1 2 ratio. These complexes have been characterized by elemental analysis, IR spectroscopy, thermogravimetry, optical properties, X-ray, and magnetic measurement studies. The X-ray structure shows that these complexes are isostruc-tural, each samarium being seven-coordinate.627... 

Variable-temperature magnetic susceptibiUty measurements confirm the structure of the complexes as well as the proton NMR spectrum of the samarium compound, which shows a sharp singlet for the 36 tert-butyl protons at 5 = — 0.79 ppm. 

Structural transition has a drastic effect on the electrical behavior of these indides (abrupt change in the slope), but no observable effect on the magnetic data (table 20). The samarium and ytterbium compoimd show non-Ciuie-Weiss behavior. Specific heat data revealed a high y coefficient of 130 mJ/molK for the cerium compound (Pleger et al., 1987). 

Kohler and Muller (1991) obtained a divalent samarium fluoroaluminate, LiSm-AlFg, by heating a confined mixture of the appropriate fluorides two days at < 700°C. In contrast to the structure of the closely related strontium and calcium analogues in which the divalent cation is coordinated octahedrally, the Sm ion coordination is trigonal prismatic. Magnetic-susceptibility measurements show temperature dependence typical of divalent samarium. 

The most reliable characteristic parameters for compoimds of the other crystal structure t5q>es can be obtained by processing the experimental data on samarium and eiuopium dictilorides. Indeed, the cooperative magnetic transition characteristic of the Eu ion in eiuopium dichloride should be observed at temperatures lower than the minimum temperature limit at which heat capacity measiuements have been performed by Tolmach et al. (1986). It follows that these data can be treated as the lattice contribution to the heat capacity of EuQ2. 

The structure and magnetic properties of samarium as the sesquioxide and the metal have been studied by Perakis and Kern (1972). Between 8(1-154 K the magnetic susceptibility of a purified Sm specimen essentially coincided with that for Sm " in monoclinic Sm203. The minimum of x (the magnetic susceptibility) was at about 350 K. 

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