Substituted systems first order transition

NMR measurements in these systems have allowed for the following. A determination of the local-polarization distribution function W(p) and the Edwards-Anderson order parameter qEA in the weak substitutional disorder limit (x=0.5) ongoing through Tc. The results showed that W(p) is asymmetric below Tc and symmetric above Tc and that qEA makes a discontinuous jump on going through Tc in view of first-order nature of this transition. 

Substitution of the cation in the solid solution system Smi R Se by, e.g., Y or La reduces the lattice parameter and the 4f-5d excitation gap, without yielding the transition into the metallic intermediate-valence phase (Gronau 1979). In fig. 3 we show the polarized Raman spectra of Smj jjY Se at 80K for x = 0, 0.25, 0.50, 0.75 and 1.0, obtained by Giintherodt et al. (1981a). For the sake of completeness, Sm, jLag jSe has also been included. For the latter sample one observes below 200 cm first-order defect-induced Raman scattering from acoustic and optical phonons which is absent in pure SmSe. The / = 1 peak of Smo gjLap osSe has drastically broadened compared to that of pure SmSe at... 

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