scholarly journals Фазовый переход в цилиндрических изинговых нанопроволоках и нанотрубках: приближение теории молекулярного поля

2019 ◽  
Vol 61 (4) ◽  
pp. 694
Author(s):  
В.А. Танрывердиев ◽  
В.С. Тагиев ◽  
М.Н. Абдуллаев ◽  
Г.Г. Керимова
Keyword(s):  
Field Theory ◽  
Phase Diagram ◽  
Transition Temperature ◽  
Exchange Interaction ◽  
Critical Behavior ◽  
Exchange Coupling ◽  
Molecular Field ◽  
Physical Parameters ◽  
Surface Exchange ◽  
The Core

AbstractWithin the approximation of the molecular field theory, the critical behavior of cylindrical Ising nanowires and nanotubes is studied. The model considered in this work consists of ferromagnetic spins S _c situated in the core of the system and ferromagnetic spins S _s situated on the surface wall; they are interconnected by the exchange coupling J _1. The transition temperature T _c for such systems has been calculated as a function of exchange interaction parameters. The influence of the surface exchange interaction and surface coupling on the magnetodynamic behavior of the system have been studied. Some characteristic properties obtained on the phase diagram are related to the ratio of characteristic physical parameters on the surface and core of the abovementioned nanostructures.

MAGNETIC PROPERTIES OF PSEUDO-BINARY Mn1−xFexSn2 ALLOYS

1993 ◽  
Vol 07 (01n03) ◽  
pp. 867-870 ◽  
Author(s):  
H. SHIRAISHI ◽  
T. HORI ◽  
Y. YAMAGUCHI ◽  
S. FUNAHASHI ◽  
K. KANEMATSU
Keyword(s):  
Field Theory ◽  
Phase Diagram ◽  
Magnetic Properties ◽  
Magnetic Susceptibility ◽  
High Temperature ◽  
Magnetic Structure ◽  
Magnetic Phase ◽  
Magnetic Phase Diagram ◽  
Molecular Field ◽  
Magnetic Phases

The magnetic susceptibility measurements have been made on antiferromagnetic compounds Mn1–xFexSn2 and the magnetic phase diagram was illustrated. The high temperature magnetic phases I and III, major phases, were analyzed on the basis of molecular field theory and explained the change of magnetic structure I⇌III occured at x≈0.8.

A Study of Exchange Interactions in R(FeCo)11TiCy (R=Y or Pr) Compounds

2011 ◽  
Vol 170 ◽  
pp. 223-226
Author(s):  
Corneliu Bazil Cizmas ◽  
Lotfi Bessais
Keyword(s):  
Magnetic Properties ◽  
Exchange Interaction ◽  
Magnetic Moment ◽  
Exchange Coupling ◽  
Interaction Strength ◽  
Exchange Interactions ◽  
Field Approximation ◽  
Molecular Field ◽  
Coupling Parameters ◽  
Structural And Magnetic Properties

The exchange interactions in PrFe11-xCoxTiCy (x=0÷2, y≤1), are analyzed on the basis of the structural and magnetic properties of polycrystalline samples. The magnetic properties of polycrystalline isomorphous compounds YFe11-xCoxTiCy have been used in order to determine the T (T=Fe+Co) sub-lattice contributions, such as the T sub-lattice mean magnetic moment and the T-T exchange interaction strength. The exchange coupling parameters JTT, JRT and the recurrent molecular field coefficients nTT, nRT have been calculated in the molecular field approximation (MCA). The effects of Co content and carbonation on the R-T (T=Fe+Co) and on the T-T exchange interactions are analyzed.

scholarly journals Strain-induced modulation of temperature characteristics in ferrimagnetic Tb–Fe films

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Shinya Ota ◽  
Pham Van Thach ◽  
Hiroyuki Awano ◽  
Akira Ando ◽  
Kentaro Toyoki ◽  
...  
Keyword(s):  
Field Theory ◽  
Magnetic Moment ◽  
Exchange Coupling ◽  
Tensile Strain ◽  
Room Temperature ◽  
Magnetic Circular Dichroism ◽  
Flexible Substrate ◽  
Molecular Field ◽  
Compensation Temperature ◽  
X Ray

AbstractThis study investigates the effect of strain on the compensation temperature of ferrimagnetic Tb–Fe films formed on a flexible substrate. The compensation temperature is determined by the anomalous Hall measurement, and an application of 1.2% tensile strain reduces the compensation temperature by 12 K. X-ray magnetic circular dichroism reveals that approximately 5% of Fe magnetic moment and approximately 1% of Tb magnetic moment are reduced by an application of 0.9% tensile strain at the room temperature. To understand the greater reduction in Fe magnetization compared with that in Tb and the compensation temperature reduction simultaneously, a model applying molecular field theory is analyzed. Changes in three types of exchange coupling between Fe and Tb atoms are speculated to be caused by the strain.

A Review of Conformal Field Theory in 2D

2014 ◽  
Vol 6 (2) ◽  
pp. 1079-1105
Author(s):  
Rahul Nigam
Keyword(s):  
Field Theory ◽  
Quantum Field Theory ◽  
Conformal Field Theory ◽  
Statistical Mechanics ◽  
Critical Behavior ◽  
Verma Module ◽  
Virasoro Algebra ◽  
Quantum Field ◽  
Conformal Field ◽  
Insight Into

In this review we study the elementary structure of Conformal Field Theory in which is a recipe for further studies of critical behavior of various systems in statistical mechanics and quantum field theory. We briefly review CFT in dimensions which plays a prominent role for example in the well-known duality AdS/CFT in string theory where the CFT lives on the AdS boundary. We also describe the mapping of the theory from the cylinder to a complex plane which will help us gain an insight into the process of radial quantization and radial ordering. Finally we will develop the representation of the Virasoro algebra which is the well-known "Verma module".  

scholarly journals Study of physical properties of a ferrimagnetic spinel Cu1.5Mn1.5O4: spin dynamics, magnetocaloric effect and critical behavior

RSC Advances ◽  
2021 ◽  
Vol 11 (41) ◽  
pp. 25664-25676
Author(s):  
Abir Hadded ◽  
Jalel Massoudi ◽  
Sirine Gharbi ◽  
Essebti Dhahri ◽  
A. Tozri ◽  
...  
Keyword(s):  
Phase Transition ◽  
Transition Temperature ◽  
Physical Properties ◽  
Magnetocaloric Effect ◽  
Phase Transition Temperature ◽  
Magnetic Phase Transition ◽  
Critical Behavior ◽  
Magnetic Phase ◽  
Spin Dynamics ◽  
Critical Behaviour

The present work reports a detailed study of the spin dynamics, magnetocaloric effect and critical behaviour near the magnetic phase transition temperature, of a ferrimagnetic spinel Cu1.5Mn1.5O4.

scholarly journals A Brief Review of Implicit Regularization and Its Connection with the BPHZ Theorem

Symmetry ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 956
Author(s):  
Dafne Carolina Arias-Perdomo ◽  
Adriano Cherchiglia ◽  
Brigitte Hiller ◽  
Marcos Sampaio
Keyword(s):  
Field Theory ◽  
Quantum Field Theory ◽  
Gauge Symmetry ◽  
Particle Physics ◽  
Analytic Extension ◽  
Quantum Field ◽  
Loop Order ◽  
Time Dimension ◽  
The Core ◽  
Striking Success

Quantum Field Theory, as the keystone of particle physics, has offered great insights into deciphering the core of Nature. Despite its striking success, by adhering to local interactions, Quantum Field Theory suffers from the appearance of divergent quantities in intermediary steps of the calculation, which encompasses the need for some regularization/renormalization prescription. As an alternative to traditional methods, based on the analytic extension of space–time dimension, frameworks that stay in the physical dimension have emerged; Implicit Regularization is one among them. We briefly review the method, aiming to illustrate how Implicit Regularization complies with the BPHZ theorem, which implies that it respects unitarity and locality to arbitrary loop order. We also pedagogically discuss how the method complies with gauge symmetry using one- and two-loop examples in QED and QCD.

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