Study of the SmBaCuO solid solutions decomposition and its possible role   for changing critical current
  We studied thermochemical characteristics of the Sm1+xBa2-xCu3Oy single crystals by solution calorimetry. Dependences of formation enthalpies from samarium content were constructed. It was established that solid solutions on the bases of Sm123 could be decomposed both in inert and in oxygen atmosphere into different mixtures. We supposed that solid solutions decomposition could lead to increasing critical current density. We assumed from thermochemical data that Jc could be greater for samples prepared in oxygen than for samples synthesized in inert atmosphere. We confirmed these assumptions by comparison of obtained thermochemical data with transport properties measured in literature. We also investigated temperature dependences of resistance in the temperature range of 300-550 K during slow heating. As it was shown there was anomaly of resistance near 500 K. The origin of this anomaly was discussed. 
N.I. Matskevich, A.I. Romanenko, L.V. Yakovkina (Institute of   Inorganic Chemistry, Siberian Branch of the Russian Academy ...