WANG–LANDAU SIMULATION ON THERMODYNAMIC AND MAGNETIC PROPERTIES OF HONEYCOMB LATTICE

2011 ◽  
Vol 25 (26) ◽  
pp. 3435-3442
Author(s):  
XIAOYAN YAO
Keyword(s):  
Magnetic Field ◽  
Monte Carlo Simulation ◽  
Magnetic Properties ◽  
Free Energy ◽  
Magnetic Susceptibility ◽  
Magnetic Property ◽  
Ground State ◽  
Antiferromagnetic Order ◽  
Honeycomb Lattice ◽  
Antiferromagnetic Ising Model

Wang–Landau algorithm of Monte Carlo simulation is performed to understand the thermodynamic and magnetic properties of antiferromagnetic Ising model on honeycomb lattice. The internal energy, specific heat, free energy and entropy are calculated to present the thermodynamic behavior. For magnetic property, the magnetization and magnetic susceptibility are discussed at different temperature upon different magnetic field. The antiferromagnetic order is confirmed to be the ground state of the system, and it can be destroyed by a large magnetic field.

Mössbauer and Magnetic Property Study on Cyano-Bridged Complex [Gu(en)x]yMA[Fe(CN)6]z·nH2O(MA=K+)

2012 ◽  
Vol 567 ◽  
pp. 21-24 ◽  
Author(s):  
Zhong Hui Ye ◽  
Qing Lin ◽  
Hai Fu Huang ◽  
Yun He ◽  
Shao Hong Chen
Keyword(s):  
Magnetic Properties ◽  
Magnetic Susceptibility ◽  
Magnetic Property ◽  
Long Range ◽  
Ground State ◽  
Antiferromagnetic Interaction ◽  
Ferromagnetic Coupling ◽  
Curie Constant ◽  
Ferromagnetic Interaction ◽  
Weiss Constant

The cyano-bridged complexe [Gu(en)x]yMA[Fe(CN)6]z·nH2O(MA=K+) have been synthesized. In the compound [Cu(en)2][KFe(CN)6]·H2O, we shows firstly a weak intramolecular anti-ferromagnetic coupling between Fe3+(ground state 5T2g, S=1/2) and Cu2+(ground state 6T2g3eg, S=1/2) through the long- range cyano bridges. The magnetic susceptibility obey the curie-weiss law [χ=C/(T-θ)] with a negative weiss constant,the curie constant C=0.42cm3·k·mol-1, the compound exists a strong Cu2+–CN–Fe3+ ferromagnetic interaction and a weak Cu2+(ground state 6T2g3eg, S=1/2)–Cu2+(ground state 6T2g3eg, S=1/2) antiferromagnetic interaction, through long range of NC-Fe-CN. At the same time, we have given an explanation from magnetic properties and struction of compounds.

scholarly journals Clarification of the Magnetocapacitance Mechanism for Fe3O4-PDMS Nanocomposites

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Chen Guobin ◽  
Yang Hui ◽  
Zhang Xiaoming ◽  
Liu Jun ◽  
Tang Jun
Keyword(s):  
Magnetic Field ◽  
Magnetic Properties ◽  
Magnetic Property ◽  
Preparation Method ◽  
Volume Fraction ◽  
Magnetic Interaction ◽  
Mechanical Parameters ◽  
Measurement Results

We mainly focused on the magnetocapacitance effect of Fe3O4-PDMS nanocomposites. We also proposed the preparation method and measured microstructures, magnetic properties, and magnetocapacitance value of the nanocomposites. The magnetocapacitance measurement results show that the nanocomposites have magnetocapacitance property, the magnetocapacitance with magnetic field depends on the magnetic property, and the value at the same magnetic field is increasing with the volume fraction of Fe3O4nanoparticles. The magnetocapacitance model is proposed to explain this phenomenon by analyzing the magnetic interaction between particles and the viscoelasticity of PDMS. We also calculated the theoretical capacitance value of all samples using the magnetization of nanoparticles and mechanical parameters of PDMS. From the theoretical values, it is concluded that the model we proposed can well explain the magnetocapacitance effect of Fe3O4-PDMS nanocomposites.

scholarly journals Manganese/Yttrium Codoped Strontium Nanohexaferrites: Evaluation of Magnetic Susceptibility and Mossbauer Spectra

Nanomaterials ◽  
2018 ◽  
Vol 9 (1) ◽  
pp. 24 ◽  
Author(s):  
Munirah Almessiere ◽  
Yassine Slimani ◽  
Hakan Güngüneş ◽  
Abdulhadi Baykal ◽  
S.V. Trukhanov ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Magnetic Properties ◽  
Magnetic Susceptibility ◽  
Mössbauer Spectra ◽  
Ac Susceptibility ◽  
Sol Gel ◽  
Hyperfine Magnetic Field ◽  
Analytical Techniques ◽  
Magnetic Interactions ◽  
Mossbauer Spectra

Manganese (Mn)- and yttrium (Y)-substituted Sr-nanohexaferrites (MYSNHFs) of composition Sr1−xMnxFe12−xYxO19 (with 0.0 ≤ x ≤ 0.5) were prepared by citrate sol-gel autocombustion method. As-prepared MYSNHFs were characterized via diverse analytical techniques to determine the influence of Mn and Y cosubstitution on their microstructures and magnetic properties. 57Fe Mössbauer spectra of the MYSNHFs were used to evaluate the variation in the line width, isomer shift, quadrupole splitting, and hyperfine magnetic field values. It was shown that the dopant ions could preferentially occupy the 12k, 4f2, and 2b sites. Furthermore, the observed shift in the blocking temperatures of the studied MYSNHFs towards lower values with rising Mn2+ and Y3+ contents was attributed to the overall particles size reduction. Meanwhile, the AC susceptibility of the proposed MYSNHFs revealed that the magnetic interactions were weakened with the increase in dopant contents which was ascribed to the replacement of both Sr2+ and Fe3+ ions by the Mn2+ and Y3+ dopants.

Magnetic Properties of Pbl-xGdxTe

1986 ◽  
Vol 89 ◽  
Author(s):  
M. Gorska ◽  
J. R. Anderson ◽  
Z. Golacki
Keyword(s):  
Magnetic Field ◽  
Magnetic Properties ◽  
Magnetic Susceptibility ◽  
Exchange Interaction ◽  
Magnetic Field Dependence ◽  
Antiferromagnetic Exchange ◽  
Brillouin Function ◽  
Parameter Values ◽  
Mn Doped ◽  
The Magnetic Field

AbstractThe magnetization and magnetic susceptibility of Bridgman-grown Pb1-xGdxTe have been measured over a temperature range from 2 to 300 K and in magnetic fields from 0.01 to 50 κOe. The x-values of the crystals ranged from 0.03 to 0.07. The magnetic susceptibility followed a Curie-Weiss behavior, χ = C/(T + θ), with positive θ implying an antiferromagnetic exchange interaction between Gd ions. The magnetic field dependence of the magnetization was fitted to a modified Brillouin function with parameter values that agreed fairly well with those from Curie-Weiss plots. The magnitude of θ was comparable to the value found for Pb1-xMnxTe for similar x values; but since the ion spin is bigger for Gd this suggests that the exchange interaction in Gd-doped PbTe is roughly half the value in Mn-doped PbTe.

THE COMPENSATION BEHAVIOR AND INITIAL SUSCEPTIBILITIES OF A MIXED-SPIN HEISENBERG FERRIMAGNETIC SYSTEM IN AN EXTERNAL MAGNETIC FIELD

2007 ◽  
Vol 21 (07) ◽  
pp. 1077-1087 ◽  
Author(s):  
JUN LI ◽  
AN DU ◽  
GUOZHU WEI
Keyword(s):  
Magnetic Field ◽  
Magnetic Properties ◽  
Transition Temperature ◽  
External Magnetic Field ◽  
Green Function ◽  
Compensation Point ◽  
Function Technique ◽  
Honeycomb Lattice ◽  
Mixed Spin ◽  
Compensation Behavior

The magnetic properties of a mixed spin-2 and spin-5 / 2 Heisenberg ferrimagnetic system on a layered honeycomb lattice are investigated theoretically by a multisublattice Green-function technique which takes into account the quantum nature of Heisenberg spins. We calculate the magnetization and the compensation temperature and transition temperature of the system in an external magnetic field and in a zero external magnetic field, and find that the transition temperature of the system increases on the effect of an external magnetic field, the compensation point disappears when the single-ion anisotropy is not large and there are two compensation points when the anisotropy is large. We also calculate the initial susceptibilities of the system.

scholarly journals A distinct magnetic property of the inner penumbral boundary

2020 ◽  
Vol 638 ◽  
pp. A28 ◽  
Author(s):  
Jan Jurčák ◽  
Markus Schmassmann ◽  
Matthias Rempel ◽  
Nazaret Bello González ◽  
Rolf Schlichenmaier
Keyword(s):  
Magnetic Field ◽  
Magnetic Properties ◽  
Magnetic Property ◽  
Potential Field ◽  
Magnetic Energy ◽  
Vertical Component ◽  
Flux Rope ◽  
Field Configuration ◽  
The Magnetic Field ◽  
Upper Boundary

Context. Analyses of sunspot observations revealed a fundamental magnetic property of the umbral boundary: the invariance of the vertical component of the magnetic field. Aims. We analyse the magnetic properties of the umbra-penumbra boundary in simulated sunspots and thus assess their similarity to observed sunspots. We also aim to investigate the role of the plasma β and the ratio of kinetic to magnetic energy in simulated sunspots in the convective motions because these quantities cannot be reliably determined from observations. Methods. We used a set of non-gray simulation runs of sunspots with the MURaM code. The setups differed in terms of subsurface magnetic field structure and magnetic field boundary imposed at the top of the simulation domain. These data were used to synthesize the Stokes profiles, which were then degraded to the Hinode spectropolarimeter-like observations. Then, the data were treated like real Hinode observations of a sunspot, and magnetic properties at the umbral boundaries were determined. Results. Simulations with potential field extrapolation produce a realistic magnetic field configuration on the umbral boundaries of the sunspots. Two simulations with a potential field upper boundary, but different subsurface magnetic field structures, differ significantly in the extent of their penumbrae. Increasing the penumbra width by forcing more horizontal magnetic fields at the upper boundary results in magnetic properties that are not consistent with observations. This implies that the size of the penumbra is given by the subsurface structure of the magnetic field, that is, by the depth and inclination of the magnetopause, which is shaped by the expansion of the sunspot flux rope with height. None of the sunspot simulations is consistent with the observed properties of the magnetic field and the direction of the Evershed flow at the same time. Strong outward-directed Evershed flows are only found in setups with an artificially enhanced horizontal component of the magnetic field at the top boundary that are not consistent with the observed magnetic field properties at the umbra-penumbra boundary. We stress that the photospheric boundary of simulated sunspots is defined by a magnetic field strength of equipartition field value.

Magnetic phenomena

2004 ◽  
Author(s):  
Robert E. Newnham
Keyword(s):  
Magnetic Field ◽  
Magnetic Properties ◽  
Magnetic Susceptibility ◽  
Magnetic Fields ◽  
Magnetic Flux ◽  
Flux Density ◽  
Magnetic Dipole ◽  
Electric Charge ◽  
Dipole Moments ◽  
Magnetic Flux Density

In this chapter we deal with a number of magnetic properties and their directional dependence: pyromagnetism, magnetic susceptibility, magnetoelectricity, and piezomagnetism. In the course of dealing with these properties, two new ideas are introduced: magnetic symmetry and axial tensors. Moving electric charge generates magnetic fields and magnetization. Macroscopically, an electric current i flowing in a coil of n turns per meter produces a magnetic field H = ni amperes/meter [A/m]. On the atomic scale, magnetization arises from unpaired electron spins and unbalanced electronic orbital motion. The weber [Wb] is the basic unit of magnetic charge m. The force between two magnetic charges m1 and m2 is where r is the separation distance and μ0 (=4π×10−7 H/m) is the permeability of vacuum. In a magnetic field H, magnetic charge experiences a force F = mH [N]. North and south poles (magnetic charges) separated by a distance r create magnetic dipole moments mr [Wb m]. Magnetic dipole moments provide a convenient way of picturing the atomistic origins arising from moving electric charge. Magnetization (I) is the magnetic dipole moment per unit volume and is expressed in units of Wb m/m3 = Wb/m2. The magnetic flux density (B = I + μ0H) is also in Wb/m2 and is analogous to the electric displacement D. All materials respond to magnetic fields, producing a magnetization I = χH, and a magnetic flux density B = μH where χ is the magnetic susceptibility and μ is the magnetic permeability. Both χ and μ are in henries/m (H/m). The permeability μ = χ + μ0 and is analogous to electric permittivity. χ and μ are sometimes expressed as dimensionless quantities (x ̅ and μ ̅ and ) like the dielectric constant, where = x ̅/μ0 and = μ ̅/μ0. Other magnetic properties will be defined later in the chapter. A schematic view of the submicroscopic origins of magnetic phenomena is presented in Fig. 14.1. Most materials are diamagnetic with only a weak magnetic response induced by an applied magnetic field.

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