This work was done in order to prepare (La1-xSrx)2 MnO4 (0.35•...x•...0.65) with K2NiF4 structure and to in vestigate their electrical properties. The La-rich (La1-xSrx)2MnO4 has been successfully prepared by a solid-state reaction method in vacuum. The lattice parameters of (La0.5Sr0.5)2MnO4 were the same as those of La2CuO4. This indicates that the Mn-O bond shrank in the a-b plane and the lattice expanded along the c-axis in the K2NiF4 structure by the co-operative Jahn-Teller effect.

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... , the lattice parameters in creased along the ƒ¿-axis and decreased along the c-axis as x deviates from x=0.5. This tendency differs from that of the (La1-xSrx)2CuO4 superconductor. The tem perature dependence of electrical resistivity of (La1-x Srx)2MnO4 obeyed the Arrhenius law. The result showed that (La1-xSrx)2MnO4 (0.35•...x•...0.65) is a semi conductor.