Abstract:
It is shown, within the framework of the generalized mean-field theory, that the ground state of a system of Ising point dipoles randomly filling the sites of a three-dimensional cubic lattice depends on the fraction $p$ of filled sites. For example, a body-centered lattice is ferromagnetic at $p>p_{c1}\approx0.55$, a spin glass at $p_{c1}<p<p_{c2}\approx0.35$, and paramagnetic at $p<p_{c2}$. The transition between these states has a percolation nature. The temperature dependences of the magnetization in the ferromagnetic phase and the susceptibility in the paramagnetic phase were determined. The magnetic phase diagram of the system was constructed.
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