Precursor nanoscale modulations in ferromagnets: Modeling and thermodynamic characterization
نویسندگان
چکیده
Using a Ginzburg-Landau model for the magnetic degrees of freedom with coupling to disorder, we demonstrate through simulations the existence of stripelike magnetic precursors recently observed in Co-Ni-Al alloys above the Curie temperature. We characterize these magnetic modulations by means of the temperature dependence of local magnetization distribution, magnetized volume fraction, and magnetic susceptibility. We also obtain a temperature-disorder strength phase diagram in which a magnetic tweed phase exists in a small region between the paramagnetic and dipolar phases.
منابع مشابه
Electrochemical Preparation and Characterization of Mn5O8 Nanostructures
Electrochemical synthesis followed by heat-treatment is a facile and easy method for preparation of nanostructured metal oxides. Herein we report nanostructured Mn5O8 prepared through pulse cathodic deposition followed by heat-treatment for the first time. For the preparation of Mn5O8 nanorods, pulse cathodic electrodeposition was first done from 0.005M Mn(NO3)2 at the current density of 5 mA c...
متن کاملSonochemical Synthesis and Characterization of a Nano-Sized Lead (II) Coordination Polymer; A New Precursor for the Preparation of PbO Nanoparticles
Development of components that can form large molecular aggregates through non–covalent interactions, in nano size structures, has been an active area of research. In current study, a nano-sized Pb(II) coordination polymer, {[Pb(pydc)(pydc.H2)(H2O)2]2}n (1), where [pydc.H2= 2,6-pyridinedicarboxylic acid), wer...
متن کاملOrigin of magnetic and magnetoelastic tweedlike precursor modulations in ferroic materials.
Based on experimental observations of modulated magnetic patterns in a Co0.5Ni0.205Ga0.295 alloy, we propose a model to describe a (purely) magnetic tweed and a magnetoelastic tweed. The former arises above the Curie (or Néel) temperature due to magnetic disorder. The latter results from compositional fluctuations coupling to strain and then to magnetism through the magnetoelastic interaction a...
متن کاملNanoscale Studies on Aggregation Phenomena in Nanofluids
Understanding the microscopic dispersion and aggregation of nanoparticles at nanoscale media has become an important challenge during the last decades. Nanoscale modeling techniques are the important tools to tackle many of the complex problems faced by engineers and scientists. Making progress in the investigations at nanoscale whether experimentally or computationally has helped understand th...
متن کاملThermodynamic transitions in inhomogeneous d-wave superconductors
We study the spectral and thermodynamic properties of inhomogeneous d-wave superconductors within a model where the inhomogeneity originates from atomic-scale pair disorder. This assumption has been shown to be consistent with the small charge and large gap modulations observed by scanning tunneling spectroscopy on Bi2Sr2CaCu2O8+x. Here we calculate the specific heat within the same model, and ...
متن کامل