Alternating commensurate-incommensurate structures in the magnetic phase diagram ofCsNiF3

Alternating commensurate - incommensurate structures in the magnetic

The magnetic phase diagram of the quasi one-dimensional spinchain system CsNiF 3 below the Néel temperature is determined. For magnetic fields perpendicular to the spin chains incommensurate phases are predicted. From linear spin-wave theory we obtain the instability line of the paramagnetic phase as a function of the strength and the direction of the field. The system undergoes a transition to...

The Commensurate Incommensurate Transition

In condensed matter physics there are many successful models of phase transitions between a more ordered and less ordered state. Break a continuous symmetry and you’ve got yourself a cpmtomipus phase transition. Roughly speaking the transition occurs when the symmetry breaking potential term becomes the dominant one in the free energy and the system ‘contracts’ in phase space decreasing entropy...

Phase diagram and commensurate-incommensurate transitions in the phase field crystal model with an external pinning potential.

We study the phase diagram and the commensurate-incommensurate transitions in a phase field model of a two-dimensional crystal lattice in the presence of an external pinning potential. The model allows for both elastic and plastic deformations and provides a continuum description of lattice systems, such as for adsorbed atomic layers or two-dimensional vortex lattices. Analytically, a mode expa...

Dislocation Structures of Submonolayer Films near the Commensurate-Incommensurate Phase Transition: Ag on Pt(111)

Submonolayer films of Ag on Pt(111) exhibit parallel partial dislocations separated by narrow hcp domains and much wider fcc domains, the large difference in width being atypical of strained metal overlayers on close-packed substrates. Using a two-dimensional Frenkel-Kontorova model, we calculate the relative domain widths. We examine possible effects of dislocations on equilibrium island shape...

Commensurate and Incommensurate Structures in a Nonequilibrium System