ISSN 1017-2548(Print)
ISSN 2234-8530(Online)
Volume 39, Number 7
JKCSEZ 39(7)
February 20, 1995 

A series of samples in the Eu1-xSrxCoO3-y system has been prepared by heating the proper amount of reactant mixture to 1150℃ under an ambient atmosphere, and the solid solutions are identified by X-ray powder diffraction analysis. The crystal system of samples for the compositions of x=0.00 and 0.25 are found to be orthorhombic whose local symmetry is similiar to the distorted octahedra with orthoferrite type one, whereas those of x=0.50 and 0.75 to be the cubic system, and that of x=1.00 to the orthorhombic similiar to be the brownmillerite type. The amount of Co4+ ion (τ value) is maximized at the composition of x=0.50, and the oxygen vacancies increase with the x value. The nonstoichiometric chemical formula of each compound could be determined from the mole ratio of Co4+ ion and oxygen vacancies. The Co3+ ion located in octahedral site has spin transition from low spin to high spin states with increasing temperature. Therefore, the effective magnetic moment of each samples obtained from the magnetic measurement is increased with the increasing temperature. The EuCoO3.00 has strong antiferromagnetic interaction between the neighboring Co3+ ions through the intermediate oxygen ions. With the increasing τ value, the absolute θp value is decreased by the ferromagnetic interaction of Co3+-O2--Co4+ and thus the θp has positive value at x=0.50.