Competition of two terms in exchange energy (A=A1+A2) for magnetic materials

For magnetic materials with exchange interaction, A=A1+A2 (A1>0, A2<0), the dominant term in the exchange energies of magnetic materials (A1 for ferromagnetism, or A2 for antiferromagnetism) favors to an order of the spins, whereas the minor term with different sign (A2 for ferromagnetism or A1 for antiferromagnetism) tends to disturb such order, and the effect of the minor term could be included as an effective temperature (Teff). The magnetism of a matter depends on the competition between the dominant term and the minor term in the exchange energies. When A1=|A2|, A=0, the materials are in the spin glass state; when A1>|A2|, there is the coexistence of FM and SG; when |A2|>A1, there is the coexistence of AFM and SG. The phase diagram has been derived based on the ratio of A1/|A2| for the ferromagnetism, antiferromagnetism and spin glass.