MAGNETIC PROPERTIES OF RANDOM MIXTURES WITH COMPETING INTERACTIONS : Co1-xMnxCl2.2H2O H. Deguchi, K. Takahashi, H. Kubo and K. Takeda J. Phys. Colloques, 49 C8 (1988) C8-1085-C8-1086 DOI: 10.1051/jphyscol:19888497