Possible magnetic significance of faults and polytypes in R2Co17compounds

A description of the structures of R2Co17as layer structures is presented and possible stacking faults and dislocations involving the layer planes are described. The significance of the planar defects observed in R2Co17and structurally similar compounds and the effects of the various rare earth ion symmetries for the 2H, 1R, 4H, 5H and 6H(1) and 6H(2) possible modifications for R2Co17compounds on magnetic anisotropy and magnetostriction are discussed. Finally the possible influence of stacking faults on these properties is considered.