MOSSBAUER STUDY OF THE LA2-XSRXNI0.99FE0.01O4+-DELTA SYSTEM

Abstract

A series of nonsuperconducting La2xSrxNi0.99Fe0.01O4+/-delta samples, with x = 0, 0.15, 0.45, 0.65 and 1.0, were prepared by solid state reaction. In the undoped system (without Fe), the c lattice parameter goes through a maximum and the a lattice parameter through a minimum at x approximately 0.5 and the cell volumen decreases steadily from x = 0 to x = 1.2. The resistivity also shows a maximum for x approximately 0.32 and then decreases until a minimum value is achieved around x approximately 1.1. Mossbauer spectra consist of three quadrupole doublets whose quadrupole splittings vary in a similar way as the c lattice parameter does with Sr content. The possibility of Jahn-Teller distortions associated with these variations is discussed.