4 Competition between J and D

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Suppose we add a positive exchange interaction to the dipolar antiferromagnet. If J is large enough the system should switch from an antiferromagnetic to a ferromagnetic configuration of spins. If you run this preset nothing happens initially. With J = 0.48 and D = 1 the antiferromagnetic state is stable (or rather metastable). Now increase J in steps of 0.01 by clicking on the arrow at the right end of the slot. Wait a little at each step as long as anything interesting is going on. Before long you see the development of a phase which is still antiferromagnetic but with a lamellar arrangement of up and down spins. (If you're lucky it will become evident that the minimum energy configuration involves a conflict between the desire to have the lamellae aligned perpendicular to the boundaries of the sample and the desire to avoid the right angle bends in the interior.)

Continue until J = D = 1, and turn on the magnetic field to see yet a different structure. H = 4 gives about as close an analogy as we can get with this small a system to the bubbles of a magnetic film bubble memory.

Now (with the field off again) increase T to 0.3 to speed things up a little and watch the changes as D is gradually reduced. The lamellar structure persists but becomes coarser, a new phase (??) at D = 0.5 with strips two lattice constants wide instead of one.

Stop for a while at D = 0.1. Is this a new antiferromagnetic phase or a ferromagnetic phase with a domain structure? Is that a meaningful distinction?