NOVEL MAGNETIC PHASES IN LA0.7SR0.3CO1-YFEYO3 LESS-THAN-OR-EQUAL-TO-Y-LESS-THAN-OR-EQUAL-TO-1.0) - A NEUTRON-DIFFRACTION STUDY

Magnetic and structural studies in the series La0.7Sr0.3Co1-xFeyO3 (0. 0 less than or equal to y less than or equal to 1.0) have been carried out by powder neutron diffraction for seven compositions correspondin g to y = 0.0, 0.1, 0.2, 0.3, 0.5, 0.7. 1.0. At one extreme of this ser ies La0.7Sr0.3CoO3 is a metallic ferromagnet with rhombohedral structu re while the other end member La0.7Sr0.3FeO3 is an antiferromagnetic i nsulator with orthorhombic structure. The transition from rhombohedral to orthorhombic crystal structure is observed with y greater than or equal to 0.5. Ferromagnetic phase is observed far y less than or equal to 0.2 and antiferromagnetic order is observed for y > 0.5. Coexisten ce of ferro-and antiferromagnetic order is observed for y = 0.5. This is supported by ac susceptibility measurements.