Structural-Chemical Mechanism of Formation of Solid Solutions in the La_2SrAl_2O_7-Ho_2SrAl_2O_7 System

摘要

The processes of phase formation in the La_2O_3-Ho_2O_3-SrO-Al_2O_3 system are investigated in the temperature range 1200-1500 deg C.The structural characteristics of the compounds described in the studied system are presented.It is established that the formation of (La_(1-x)Ho_xSrAl_2O_7 solid solutions proceeds through the formation of LaAlO_3,LaSrAlO_4,SrAl_2O_4,and SrHo_2O_4 compounds.An increase in the holmium content and the temperature leads to a crossover from the mechanism in which the interaction of LaAlO_3 and LaSrAlO_4 is a limiting stage to the mechanism in which the decisive role is played by the interactions of SrAl_2O_4 with Ho_2O_3 and SrHo_2O_4 with Al_2O_3.