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Monte Carlo simulation and theory in Gaussian approximation of a phase transition in the nuclear spin system of a solid

Journal Article:

Abstract

A phase transition of the nuclear spin system of a solid with dipolar and indirect scalar interactions is considered. Monte Carlo simulations of the spin-system isothermic states and of the adiabatic demagnetization process have been made. The structures and energies of the ground states and the values of the critical temperatures, T[sub C], and minimal polarizations, [rho][sub C], at which adiabatic demagnetization leads to spontaneous spin ordering, calculated for the GaAs and CaF[sub 2] nuclear spin systems, are presented. The results of numerical simulations are compared with the experimental data for CaF[sub 2]. The Weiss-field model is extended to the case of adiabatic demagnetization. The fluctuations of the local field are taken into account in the Gaussian approximation. It is shown that the proposed approach allows one to obtain asymptotically correct results both for T >> T[sub C] and T << T[sub C]. The results of the calculations in the Gaussian approximation are compared with the numerical simulations. (10 refs., 9 figs., tab.).
Authors:
Merkulov, I A; Papava, Y I; Ponomarenko, V V; [1]  Vasiliev, S I [2] 
  1. Leningradskij Gosudarstvennyj Univ., Leningrad (Russian Federation)
  2. Carleton Univ., Ottawa, ON (Canada). Dept. of Physics
Publication Date:
Feb 01, 1988
Product Type:
Journal Article
Reference Number:
AIX-25-012094; EDB-94-040554
Resource Relation:
Journal Name: Canadian Journal of Physics; (Canada); Journal Volume: 66:2
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ADIABATIC DEMAGNETIZATION; PHASE TRANSFORMATIONS; GALLIUM ARSENIDES; CALCIUM FLUORIDES; CRITICAL TEMPERATURE; ISOTHERMAL PROCESSES; MONTE CARLO METHOD; SOLIDS; SPIN EXCHANGE; ALKALINE EARTH METAL COMPOUNDS; ARSENIC COMPOUNDS; ARSENIDES; CALCIUM COMPOUNDS; CALCIUM HALIDES; CALCULATION METHODS; DEMAGNETIZATION; FLUORIDES; FLUORINE COMPOUNDS; GALLIUM COMPOUNDS; HALIDES; HALOGEN COMPOUNDS; PHYSICAL PROPERTIES; PNICTIDES; THERMODYNAMIC PROPERTIES; TRANSITION TEMPERATURE; 661300* - Other Aspects of Physical Science- (1992-)
OSTI ID:
5480000
Country of Origin:
Canada
Language:
English
Other Identifying Numbers:
Journal ID: ISSN 0008-4204; CODEN: CJPHAD
Submitting Site:
INIS
Size:
Pages: 135-144
Announcement Date:

Journal Article:

Citation Formats

Merkulov, I A, Papava, Y I, Ponomarenko, V V, and Vasiliev, S I. Monte Carlo simulation and theory in Gaussian approximation of a phase transition in the nuclear spin system of a solid. Canada: N. p., 1988. Web.
Merkulov, I A, Papava, Y I, Ponomarenko, V V, & Vasiliev, S I. Monte Carlo simulation and theory in Gaussian approximation of a phase transition in the nuclear spin system of a solid. Canada.
Merkulov, I A, Papava, Y I, Ponomarenko, V V, and Vasiliev, S I. 1988. "Monte Carlo simulation and theory in Gaussian approximation of a phase transition in the nuclear spin system of a solid." Canada.
@misc{etde_5480000,
title = {Monte Carlo simulation and theory in Gaussian approximation of a phase transition in the nuclear spin system of a solid}
author = {Merkulov, I A, Papava, Y I, Ponomarenko, V V, and Vasiliev, S I}
abstractNote = {A phase transition of the nuclear spin system of a solid with dipolar and indirect scalar interactions is considered. Monte Carlo simulations of the spin-system isothermic states and of the adiabatic demagnetization process have been made. The structures and energies of the ground states and the values of the critical temperatures, T[sub C], and minimal polarizations, [rho][sub C], at which adiabatic demagnetization leads to spontaneous spin ordering, calculated for the GaAs and CaF[sub 2] nuclear spin systems, are presented. The results of numerical simulations are compared with the experimental data for CaF[sub 2]. The Weiss-field model is extended to the case of adiabatic demagnetization. The fluctuations of the local field are taken into account in the Gaussian approximation. It is shown that the proposed approach allows one to obtain asymptotically correct results both for T >> T[sub C] and T << T[sub C]. The results of the calculations in the Gaussian approximation are compared with the numerical simulations. (10 refs., 9 figs., tab.).}
journal = {Canadian Journal of Physics; (Canada)}
volume = {66:2}
journal type = {AC}
place = {Canada}
year = {1988}
month = {Feb}
}