Magnetic behaviour of quasi-one-dimensional oxides, Ca<SUB>3</SUB>Co<SUB>1+x</SUB>Mn<SUB>1−x</SUB>O<SUB>6</SUB>

The results of ac and dc magnetization and heat capacity measurements on the oxides, Ca3Co1+xMn1&#8722;xO6, forming in a K4CdCl6-derived rhombohedral quasi-one-dimensional crystal structure, are reported. As far as Ca3Co2O6 is concerned, the results reveal a truly complex nature of the two magnetic transitions, identified to set in at 24 and 12 K in the previous literature. However, partial replacement of Co by Mn apparently results in a long magnetic ordering of an antiferromagnetic type (below 13 and 18 K for x=0.0 and 0.25, respectively), instead of spin-glass freezing in spite of the fact that there is Co-Mn disorder; in addition, interestingly there are hysteretic spin reorientation effects as revealed by the isothermal magnetization behavior