New Type Of Phase Transition Research Articles

Superfluid experiments support Kosterlitz–Thouless theory

Five years ago Michael Kosterlitz and David Thouless predicted that in the x–y or planar model of two‐dimensional substances, a new type of phase transition would occur. In a two‐dimensional superfluid, for example, at low temperatures the system would be arranged as bound vortex‐antivortex pairs whose dissociation leads to the transition. More recently David Nelson and Kosterlitz suggested that the theory could be tested experimentally by looking for a universal jump in the superfluid density at the Kosterlitz–Thouless phase transition.

Monte Carlo simulations of the two-dimensional quantal and classical spin systems — A new type of phase transition with vortices

A new type of phase transition has been found in the two-dimensional XY-model using Monte Carlo simulations, which show a divergence of susceptibility, but no divergence of specific heat. Vortices appear below T c as was predicted by Kosterlitz and Thouless.

A new type of phase transition in M(ClO4)2(H2O)6 M = Fe, Co, Ni and Mn

Abstract Mossbauer studies on Fe(ClO 4 ) 2 (H 2 O) 6 salt showed anomalous quadrupole splitting around (230 ± 15)°K which we have established to be due to a new type of phase transition from pseudohexagonal to monoclinic system. Exactly similar type of transition was observed magnetically in all the isomorphous Ni 2+ , Co 2+ and Mn 2+ perchlorate hexahydrate single crystals at different critical temperatures.

New Type of Phase Transition

It is shown that the ferromagnetic Ising model on a Cayley tree lattice exhibits a new type of phase transition at the field $B=0$ below the Bethe-Peierls transition temperature ${T}_{\mathrm{BP}}$. The leading nonanalytic part of the free energy is of the form ${B}^{\ensuremath{\kappa}}$, where the critical exponent $\ensuremath{\kappa}(T)$ increases smoothly from one to infinity as the temperature goes from 0 to ${T}_{\mathrm{BP}}$. This implies a transition of continuous order $\ensuremath{\kappa}$.