Magnetic properties of a fullerene-like X20 structure with embedded metal atom

2021 ◽  
Author(s):  
Zhong-yue Gao ◽  
Dan Lv ◽  
Wei Wang ◽  
Linmei Yang ◽  
Lei Sun ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Metal Atom ◽  
Exchange Coupling ◽  
Blocking Temperature ◽  
Physical Parameters ◽  
Double Loop ◽  
Zero Temperature ◽  
Mixed Spin ◽  
Surface Shell ◽  
The Magnetic Field

Abstract Monte Carlo simulation has been used to study magnetic and thermodynamic properties of a ferrimagnetic mixed-spin (1, 3/2) Ising fullerene-like X20 structure with embedded metal atom. Under the influence of the anisotropy and the concentration of surface shell atom, the system tends to show the multiple stable saturation values of magnetization (M=0.91, 0.85, 0.77, 0.64, 0.50 and 0.023) and the values of intermediate metastable magnetization (M=0.88, 0.76 and 0.60) at zero temperature. The blocking temperature TB becomes higher by decreasing the anisotropies (|DC |, |DS |), or increasing the exchange coupling |JCS |, the magnetic field h and the concentration of surface shell atom PS . Some interesting phenomena have been found such as the double-loop hysteresis behavior for the relatively large values of |DS | (≥2.0), originating from the competition between different physical parameters.

scholarly journals Insight into dynamic magnetic properties of YMnO3/FM bilayer in a time-dependent magnetic field

2021 ◽  
Author(s):  
Chun-lu Chang ◽  
Wei Wang ◽  
Dan Lv ◽  
Zhen-yu Liu ◽  
Ming Tian
Keyword(s):  
Magnetic Field ◽  
Magnetic Properties ◽  
Dynamic Properties ◽  
Hysteresis Loops ◽  
Time Dependent ◽  
Blocking Temperature ◽  
Physical Parameters ◽  
Present System ◽  
Mixed Spin ◽  
Insight Into

Abstract Based on the Monte Carlo simulation, a mixed-spin (5/2, 2, 3/2) Ising model is constructed to investigate the dynamic magnetic properties of antiferromagnetic/ferromagnetic YMnO 3 /FM bilayer under the existence of a time-dependent magnetic field. The effects of exchange interaction, oscillating magnetic field as well as temperature are involved in this work. Masses of numerical results of the dynamic order parameter, susceptibility, internal energy, and blocking temperature are obtained with diverse physical parameters. Moreover, the phase diagrams and the hysteresis loops of the system are discussed in detail as well for a better understanding of the dynamic properties of the present system.

HEXAGON-STRIPE TRANSITION AT THE MAGNETIC FIELD INDUCED PHASE TRANSFORMATIONS OF THE MAGNETORHEOLOGICAL SUSPENSIONS

2002 ◽  
Vol 16 (17n18) ◽  
pp. 2345-2351 ◽  
Author(s):  
A. CEBERS
Keyword(s):  
Magnetic Field ◽  
Numerical Simulation ◽  
Physical Parameters ◽  
Phase Boundaries ◽  
Modulated Phases ◽  
Magnetorheological Suspensions ◽  
Perturbed State ◽  
Magnetorheological Suspension ◽  
The Magnetic Field ◽  
Hele Shaw Cell

The phase diagram of the magnetorheological suspension allowing for the modulated phases in the Hele-Shaw cell under the action of the normal field is calculated. The phase boundaries between the stripe, the hexagonal and the unmodulated phases in dependence on the layer thickness and the magnetic field strength are found. The existence of the transitions between the stripe and the hexagonal phases at the corresponding variation of the physical parameters is illustrated by the numerical simulation of the concentration dynamics in the Hele-Shaw cell. It is remarked that those transitions in the case of the magnetorheological suspensions can be caused by the compression or the expansion of the layer. Among the features noticed at the numerical simulation of the concentration dynamics in the Hele-Shaw cell are: the stripe patterns formed from the preexisting hexagonal structures are more ordered than arising from the initial randomly perturbed state; at the slightly perturbed boundary between the concentrated and diluted phases the hexagonal and the inverted hexagonal phases are formed and others.

Numerical and Statistical Analysis of Dissipative and Heat Absorbing Graphene Maxwell Nanofluid Flow Over a Stretching Sheet

2021 ◽  
Vol 10 (4) ◽  
pp. 600-607
Author(s):  
A. Bhattacharyya ◽  
R. Sharma ◽  
M. K. Mishra ◽  
Ali J. Chamkha ◽  
E. Mamatha
Keyword(s):  
Magnetic Field ◽  
Nusselt Number ◽  
Numerical Solution ◽  
Physical Parameters ◽  
Nonlinear Mathematical Model ◽  
Nanofluid Flow ◽  
Maxwell Nanofluid ◽  
Highly Nonlinear ◽  
Numeric Data ◽  
The Magnetic Field

This paper is basically devoted to carry out an investigation regarding the unsteady flow of dissipative and heat absorbing hydromagnetic graphene Maxwell nanofluid over a linearly stretched sheet taking momentum and thermal slip conditions into account. Ethylene glycol is selected as a base fluid while graphene particles are considered as nanoparticles. The highly nonlinear mathematical model of the problem is converted into a set of nonlinear coupled differential equations by means of fitting similarity variables. Further, Runge-Kutta Fehlberg algorithms along with the shooting scheme are instigated to analyse the numerical solution. The variations in graphene Maxwell nanofluid velocity and temperature owing to different physical parameters have been demonstrated via numerous graphs whereas Nusselt number and skin friction coefficients are illustrated in numeric data form and are reported in different tables. In addition, a statistical method is implemented for multiple quadratic regression estimation analysis on the numerical figures of wall velocity gradient and local Nusselt number to establish the connection among heat transfer rate and physical parameters. Our numerical findings reveal that the magnetic field, unsteadiness, inclination angle of magnetic field and porosity parameters boost the graphene Maxwell nanofluid velocity while Maxwell parameter has a reversal impact on it. The regression analysis confers that Nusselt number is more prone to heat absorption parameter as compared to Eckert number. Finally, the numerical findings are compared with those of earlier published articles under restricted conditions to validate the numerical solution. The comparison of numerical findings shows an excellent conformity among the results.

In Search of the Jerk Element

2021 ◽  
Author(s):  
Zachary P. Belyaev ◽  
Samuel N. Downes ◽  
Philip A. Voglewede
Keyword(s):  
Magnetic Field ◽  
Motion Planning ◽  
System Performance ◽  
Theoretical Background ◽  
Physical Parameters ◽  
Common Elements ◽  
Planning And Control ◽  
Magneto Rheological ◽  
And Control ◽  
The Magnetic Field

Abstract Mechanical components, such as springs, dampers and mass, alter and influence an engineered system’s motion based upon a system’s position, velocity and acceleration, respectively. This paper aims to discover and develop another element (dubbed the damper) which provides a force proportional to a system’s jerk (i.e., the derivative of acceleration) to better engineer a system’s response. By utilizing the known applications of jerk in motion planning and control theory, existing possible physical implementations and uses of jerk and the jerk element are discussed in relation to its influence on the system’s response, specifically vibration. Using a Buckingham Pi approach, the theoretical background of the jerk element is presented and possible physical parameters are combined to show how the jerk element could be created from common elements and parameters. The most promising approach of varying the magnetic field of existing magneto-rheological dampers is developed to give an example of the jerk element along with the difficulties and concerns in developing the jerk element. This paper serves less of a purpose towards answering all questions of the jerk element, but rather focuses more on posing the appropriate questions which sets the stage for an easily realizable future jerk element which can improve system performance.

scholarly journals Analytical model for cluster radio relics

2020 ◽  
Vol 493 (2) ◽  
pp. 2306-2317 ◽  
Author(s):  
M Brüggen ◽  
F Vazza
Keyword(s):  
Magnetic Field ◽  
Flux Distribution ◽  
Cosmic Ray ◽  
Analytical Models ◽  
Physical Parameters ◽  
Mass Relation ◽  
Intracluster Medium ◽  
Large Area ◽  
Shock Dynamics ◽  
The Magnetic Field

ABSTRACT Radio relics are vast synchrotron sources that sit on the outskirts of merging galaxy clusters. In this work we model their formation using a Press–Schechter formalism to simulate merger rates, analytical models for the intracluster medium and the shock dynamics, as well as a simple model for the cosmic ray electrons at the merger shocks. We show that the statistical properties of the population of radio relics are strongly dependent on key physical parameters, such as the acceleration efficiency, the magnetic field strength at the relic, the geometry of the relic and the duration of the electron acceleration at merger shocks. It turns out that the flux distribution as well as the power–mass relation can constrain key parameters of the intracluster medium. With the advent of new large-area radio surveys, statistical analyses of radio relics will complement what we have learned from observations of individual objects.

Waves in a cold plasma with spatially periodic sheared fields

1989 ◽  
Vol 42 (1) ◽  
pp. 153-164 ◽  
Author(s):  
D. A. Diver ◽  
E. W. Laing ◽  
C. C. Sellar
Keyword(s):  
Magnetic Field ◽  
Wave Propagation ◽  
Cold Plasma ◽  
Density Fluctuations ◽  
Rotating Magnetic Field ◽  
Physical Parameters ◽  
Order Ordinary Differential Equation ◽  
Spatially Periodic ◽  
Constant Magnitude ◽  
The Magnetic Field

We have studied wave propagation in a cold plasma, in the presence of a spatially rotating magnetic field of constant magnitude. New features introduced by this variation include streaming velocities and a plasma current in equilibrium and density fluctuations. We present only the case of wave propagation along the axis of rotation of the magnetic field. A set of ordinary differential equations for the electric field components is obtained, which may be combined into a single fourth-order ordinary differential equation with periodic coefficients. Solutions are obtained in closed form and their nature is determined in terms of the physical parameters of the System, magnetic field strength, number density and wave frequency.

scholarly journals Effect of Magnetic Field and Temperature on the Exchange Bias in Phase-Separated Nd1-xSrxCoO3(x=0.10, 0.15)

2015 ◽  
Vol 9 (1) ◽  
pp. 56-59 ◽  
Author(s):  
Yi-Yun Yang
Keyword(s):  
Magnetic Field ◽  
Exchange Bias ◽  
Exchange Coupling ◽  
Hysteresis Loops ◽  
Freezing Temperature ◽  
Solid State Reaction Method ◽  
Conventional Solid State Reaction ◽  
Magnetic Field Axis ◽  
Coexisting Phases ◽  
The Magnetic Field

The exchange bias phenomena of phase-separated Nd1-xSrxCoO3(x=0.10, 0.15) samples were systematically investigated in this paper. The samples were prepared using conventional solid state reaction method. When the NdSrCoO samples cooled down in magnetic field below freezing temperature, the hysteresis loops shifted along the magnetic field axis. Moreover, exchange bias of Nd1-xSrxCoO3 is strongly dependent on the field and the temperature. The influence of magnetic field on the relative ratio of the coexisting phases may be responsible for these behaviors. Therefore, our study confirmed that in phase-separated system, the exchange coupling at the interface between the ferromagnetism clusters and the spin glass regions may induce interfacial exchange anisotropy.

scholarly journals Numerical Model for Determining the Magnetic Loss of Magnetic Fluids

Materials ◽  
2019 ◽  
Vol 12 (4) ◽  
pp. 591
Author(s):  
Miloš Beković ◽  
Mislav Trbušić ◽  
Sašo Gyergyek ◽  
Mladen Trlep ◽  
Marko Jesenik ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Magnetic Fluid ◽  
Magnetic Loss ◽  
Linear Response Theory ◽  
Heating Power ◽  
Field Energy ◽  
Physical Parameters ◽  
Therapeutic Effects ◽  
High Heating ◽  
The Magnetic Field

Magnetic fluid hyperthermia (MFH) is a medical treatment where the temperature in the tissue is increased locally by means of heated magnetic fluid in an alternating magnetic field. In recent years, it has been the subject of a lot of research in the field of Materials, as well as in the field of clinical testing on mice and rats. Magnetic fluid manufacturers aim to achieve three objectives; high heating capacity, biocompatibility and self-regulatory temperature effect. High heating power presents the conversion of magnetic field energy into temperature increase where it is challenging to achieve the desired therapeutic effects in terms of elevated temperature with the smallest possible amount of used material. In order to carry out the therapy, it is primarily necessary to create a fluid and perform calorimetric measurement for determining the Specific Absorption Rate (SAR) or heating power for given parameters of the magnetic field. The article presents a model based on a linear response theory for the calculation of magnetic losses and, consequently, the SAR parameters are based on the physical parameters of the liquid. The calculation model is also validated by calorimetric measurements for various amplitudes, frequencies and shapes of the magnetic field. Such a model can serve to help magnetic fluid developers in the development phase for an approximate assessment of the heating power.

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