PREPARATION AND CHARACTERIZATION OF FULLY STOICHIOMETRIC SRCOO3 BY ELECTROCHEMICAL OXIDATION

A nearly stoichiometric SrCoO3 phase had been prepared up to now only using high oxygen pressure. A new method for preparing fully stoichiometric SrCoO3 has been proposed using electrochemical oxidation. Brownmillerite-type SrCoO2.50 is oxidized into a completely stoichiometric perovskite at a potential of 500 mV for 180 hours at room temperature in alkaline media (1 M KOH). The oxidized phase has a cubic unit cell (a = 383.5 pm). It is metallic and, at temperatures below T = 280 K, it shows ferromagnetic behavior. The magnetic moment at 0 K is 2.1 mu(B). The physical properties of SrCoO3.00 have been explained in terms of partial occupancy of a sigma*e(g)alpha band.