Behaviour at ok and at different magnetic fields of the double magnetic helix

We study the behaviour at 0K and at all magnetic field values up to the magnetic saturation of the magnetic helix in which two distinct magnetic ions of spin lengths S₁, and S₂ are acted on by two unequal molecular fields. Although limited to the case of zigzag and collinear chains on which only the magnetic interactions J between first nearest neighbours (n.n) and J₁, or J₁ between second n.n. are considered, complex phase diagrams are obtained. The most disclosing features show up by taking S₁, S₂, J₁,J₂ as parameters and h, J as variables. Whereas the biconical configuration appears as the most general solution, triangular and oblique configurations also exist in finite field in all (h, J) diagrams. In addition, a collinear ferrimagnetic configuration is found to be stable for definite h and J values. We finally observe that according to the ratio values S₁S₂ and $\text{(J}{}_2\text{J}{}_1\text{)}\text{1}\text{2}$, eight types of (h, J) diagrams exist which differ from each other by distinct approaches to the ferri- or ferromagnetic alignment.