Strontium temperature dependence

A long time passed between the first discovery of AE3(BN2)2 phases [17] (AE = Ca, Sr) and their structural characterizations [18, 19]. Two distinct phases are known to exist for both calcium and strontium nitridoborate, denoted as low-temperature y9-AE3(BN2)2 and high-temperature a-AE3(BN2)2 [20]. Their phase transitions have been studied by temperature-dependent XRD, thermo-... 

Zhu and MacDougall (1998) showed that calcium isotope composition of the shells was both species and temperamre dependent and that river water is depleted by 2%o relative to seawater. The temperature dependency of calcium isotope fractionation enables this tracer to be a potential paleotem-peramre proxy (Nagler et al., 2000). The seawater Cal" Ca secular variations are indicated by the results of De La Rocha and De Paolo (2000) for the last 160 Myr, and by the data of Zhu (1999) for the entire 3.4 Gyr of earth history. The latter indicate that, in analogy to strontium isotopes (Veizer and Compston, 1976), the Archean samples have C Ca ratios similar to the earth mantle, with the crustal-like values first appearing at the Archean/Proterozoic transition. However, in contrast to the strontium isotope trend, the calcium isotope ratios appear to dip towards mantle values also at —1.6 Gyr ago. 

The vapour pressures of calcium and strontium have been determined by a transpiration method at 1126—1300 and 1086—1310 K, respectively. The temperature dependence of the vapour pressure is given by the equations... 

It is risky, of course, to generalize from one oxide to another, but in the absence of adequately completed studies with anyone of the oxides, the assumption concerning the density of carriers seems justified. All of the superconducting oxides display R(T)fs similar to those cited above. In the case of strontium titanate, SrTiOg.., Schooley et al. (15) have shown that the critical superconducting temperature determined from the midpoints of the abrupt decreases in the resistance vs temperature and the magnetic susceptibility vs temperature depend on the density of carriers determined from measurements of Hall coefficients. Thus the results of Tc vs density of carriers is shown in Figure 4. Therein, one observes that the Tc s from both R(T) and x(T) increase to maxima near 10 carriers cm 3 and thereafter they decrease. 

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. 

Fietzke, J. and Eisenhauer, A. (2006) Determination of temperature-dependent stable strontium isotope (88gr/86gr) fractionation via bracketing standard MC-ICP-MS. Geochem. Geophys. Geosyst., 7, 1-6. 

Shao and Haile (2004) suggested a material based on strontium-doped barium cobaltite ferrite [BaFe03 Bai xSrjcCoyFei 3,03 (BSCF) (0.1 data reported by Wei et al. (2005), difficulties arise because of the complex temperature dependence of the thermal expansion coefficient. According to results obtained by Lim et al. (2(K)7), this coefficient matches that of the electrolyte when x = 0.2. 

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