Phase diagram of a three-dimensional dipolar model on an fcc lattice

Control of the supercrystallinity, nanocrystallinity, morphology and magnetism of cobalt nanoparticle assemblies. Towards novel colloidal crystals with high magnetic anisotropy

“…When translating in terms of  d for a fixed value of the magnetization curves on the model used in Ref. [22] confirm qualitatively this picture.…”

“…In Ref. [22] we determined the magnetic phase diagram of dipolar hard spheres fixed on a FCC lattice which models the colloidal crystal in the macro-spin approximation in terms of the MAE coupling measured by the ratio of the MAE ( u ) to the DDI ( d ) energies,…”

“…The result is a transition temperature, say T c ( d ), roughly proportional to  d in both the weak and strong coupling regimes with a proportionality factor T c * ( u ) (see Ref. [22]) which takes a value close to T c * ( u =0) = 0,60 and T c * ( u =∞) = 1,0 in the weak and strong  u coupling regimes respectively. At fixed value of the MAE,  u →0 and  u → ∞ correspond to the strong and weak dipolar coupling respectively where the system undergoes either a super-ferromagnetic or a super spin-glass transition respectively in agreement with the picture outlined in Ref.…”

Magnetic ordering of random dense packings of freely rotating dipoles

“…The role played by the degree of orientational disorder, called texturation, in the magnetic order has been studied by MC simulations both in FCC lattices and in RDP. [18][19][20] In particular, the phase diagram of nontextured FCC systems has been obtained as a function of E a /E dd , 21 where the ratio E a /E dd is an estimate the degree of disorder in such non-textured lattices.…”

Disorder-averaged Binder ratio in site-diluted Heisenberg models

“…Physical systems investigated in statistical mechanics are frequently considered on a model level and treated with Monte Carlo approaches. For example, magnets are modeled by systems of either Ising 1 (quantum) or Heisenberg [2][3][4][5] (quasi-classical) spins, interacting via distance-dependent exchange interactions. Then, the critical properties one is interested in are usually described in terms of the so-called phenomenological couplings, such as the Binder ratios of cumulants 6 .…”