MAGNETIC PROPERTIES OF COBR2.6H2O

Magnetic susceptibility and antiferromagnetic resonance experiments were carried out on single crystals of CoBr2·6H2O. These experiments showed that the antiferromagnetic properties of this satl are quite similar to those of the corresponding chloride. The bromide also shows large magnetic anisotropy; thus, in interpreting the results of these experiments, it was found necessary to use the theory developed by M. Date explicitly for such a case. From the experimental data, the anisotropy between the easy or preferred crystalline c axis and the intermediate b axis is 1.3×105 erg/cm3; and the anisotropy between the c axis and the least preferred a* axis, 20.4×105 erg/cm3. A study of the effects of the orthorhombic crystal field on the cobaltous ion, together with a calculation of the dipolar contribution to the magnetic anisotropy, leads to an overestimate of this anisotropy by about fifty percent. Some consideration is given to the sources of this discrepancy. © 1968, THE PHYSICAL SOCIETY OF JAPAN. All rights reserved.