Absence of Dipole Glass Transition for Randomly Dilute Classical Ising Dipoles
نویسندگان
چکیده
Dilute dipolar systems in three dimensions are expected to undergo a spin glass transition as the temperature decreases. Contrary to this, we find from Wang-Landau Monte Carlo simulations that at low concentrations x, dipoles randomly placed on a cubic lattice with dipolar interactions do not undergo a phase transition. We find that in the thermodynamic limit the “glass” transition temperature Tg goes to zero as 1/ √ N where N is the number of dipoles. The entropy per particle at low temperatures is larger for lower concentrations (x = 4.5%) than for higher concentrations (x = 20%).
منابع مشابه
Monte Carlo study of the spin-glass phase of the site-diluted dipolar Ising model
By tempered Monte Carlo simulations, we study site-diluted Ising systems of magnetic dipoles. All dipoles are randomly placed on a fraction x of all L3 sites of a simple cubic lattice, and point along a given crystalline axis. For xc x 1, where xc 0.65, we find an antiferromagnetic phase below a temperature which vanishes as x→xc from above. At lower values of x, we find an equilibrium spin-gla...
متن کاملFerroelectric and Dipolar Glass Phases of Non-Crystalline Systems
In a recent letter [Phys. Rev. Lett. 75, 2360 (1996)] we briefly discussed the existence and nature of ferroelectric order in positionally disordered dipolar materials. Here we report further results and give a complete description of our work. Simulations of randomly frozen and dynamically disordered dipolar soft spheres are used to study ferroelectric ordering in non-crystalline systems. We a...
متن کاملEquilibrium spin-glass transition of magnetic dipoles with random anisotropy axes on a site-diluted lattice
We study partially occupied lattice systems of classical magnetic dipoles which point along randomly oriented axes. Only dipolar interactions are taken into account. The aim of the model is to mimic collective effects in disordered assemblies of magnetic nanoparticles. From tempered Monte Carlo simulations, we obtain the following equilibrium results. The zero-temperature entropy approximately ...
متن کاملHigh order perturbation study of the frustrated quantum Ising chain
In this paper, using high order perturbative series expansion method, the critical exponents of the order parameter and susceptibility in transition from ferromagnetic to disordered phases for 1D quantum Ising model in transverse field, with ferromagnetic nearest neighbor and anti-ferromagnetic next to nearest neighbor interactions, are calculated. It is found that for small value of the frustr...
متن کاملThe role of luminance contrast in the detection of global structure in static and dynamic, same- and opposite-polarity, Glass patterns
Perception of global structure conveyed in static Glass patterns is difficult, though not impossible, when the constituent dipoles are formed by partnering opposite polarity dots. We investigate whether the addition of motion signals to opposite-polarity Glass patterns can act to restore the perception of global structure. The stimuli were concentric Glass patterns consisting of 200 dipoles con...
متن کامل