PROPERTIES OF LACO1-TCRTO3 - IV - STRUCTURE AND MAGNETISM

The structural and magnetic properties of the perovskite-type LaCo1-tC rtO3 phase (0 less than or equal to t less than or equal to 1) have be en studied by powder X-ray and neutron diffraction and by magnetic sus ceptibility measurements between 5 and ca. 1100 K. In the Co-rich comp osition range with an LaAlO3-type atomic arrangement 0 less than or eq ual to t<similar to 0.7 at T<200 K), LaCo1-tCrtO3 undergoes a number o f composite 'spin' conversion processes. In the Cr-rich composition ra nge with a GdFeO3-type atomic arrangement (similar to 0.7<t less than or equal to 1 at T<200K), an antiferromagnetic ordering of the 'spins' is adopted. The antiferromagnetic ordering also extends into the LaAl O3-type region and is observed in LaCo0.60Cr0.40O3, with a superimpose d ferromagnetic component below ca. 100 K according to magnetic suscep tibility measurements. The findings are discussed in relation to curre nt apprehensions of the properties of the end phases LaCoO3 and LaCrO3 .