Internal chemical pressure effect and magnetic properties of La-0.6(Sr0.4-xBax)MnO3

The effect of isovalent chemical substitution of Ba2+ into the Sr2+ sites o n the structural and magnetic transition in La-0.6(Sr0.4-xBax)MnO3 (x = 0-0 .4) has been investigated. The rhombohedral structure with space group R-3c is observed in this series of materials. Substitution of Sr and Ba in the La site changes the structural parameters such as the Mn-O bond lengths, th us allowing the study of the effect of the structure on magnetic properties . An increase in the Mn-O bond distance with increasing Ba content leads to a decrease in T-C (the temperature of the paramagnetic to ferromagnetic tr ansition). (C) 2001 Academic Press.