ISSN 1017-2548(Print)
ISSN 2234-8530(Online)
Volume 38, Number 11
JKCSEZ 38(11)
October 20, 1994 

The Sr1-xYxMnO3 (x = 0.0∼1.0) system was synthesized using amorphous citrate process. The stability of various structures and the electronic transport properties of this system were investigated. X-ray diffraction study indicated that the Sr1-xYxMnO3 system has three different structures depending on composition, namely, 4L-hexagonal perovskite (when x is less than 0.3), pseudocubic perovskite (when x is 0.3∼0.7), and hexagonal nonperovskite (when x is larger than 0.7) structures. The structural changes and electronic properties were interpreted based on two factors, i.e., the size of cations and the oxidation state of manganese ion. When the concentration of Y substitution exceeds 30%, the Mn-Mn repulsive interaction dominates over intermetallic attraction, and thus structure changes to pseudocubic perovskite. In perovskite phase the unit cell dimensions increases with increasing Mn3+ ions due to yttrium substitution. The band gap of Sr0.9Y0.1MnO3 is greater than that of Sr0.5Y0.5MnO3. The greater band gap of Sr0.9Y0.1MnO3 indicates that the 4L-hexagonal structure is more stabilized than cubic perovskite due to the Mn-Mn bond.