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Landau theory

About: Landau theory is a research topic. Over the lifetime, 2882 publications have been published within this topic receiving 57078 citations.


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Book
01 Aug 1987
TL;DR: In this paper, the basic principles and techniques of Landau's theory are presented for teaching purposes, and the practical methods for applying the theory to complex systems are described. But the main purpose of the book is to incorporate the developments which have arisen in the last fifteen years from the extensive application of the theory on a variety of physical systems.
Abstract: The contents of this book stems from three different objectives. First, it is an introduction to the basic principles and techniques of Landau's theory, which is intended for teaching purposes. A second purpose of the book provides the practical methods for applying Landau's theory to complex systems. The last objective of the book is to incorporate the developments which have arisen in the last fifteen years from the extensive application of the theory to a variety of physical systems.

454 citations

Journal ArticleDOI
TL;DR: This phenomenological theory explains the experimental observation that the spontaneous polarization is restricted to lie along the crystal b axis and predicts that the magnitude should be proportional to a magnetic order parameter.
Abstract: We show that long-range ferroelectric and incommensurate magnetic order appear simultaneously in a single phase transition in Ni3V2O8. The temperature and magnetic-field dependence of the spontaneous polarization show a strong coupling between magnetic and ferroelectric orders. We determine the magnetic symmetry using Landau theory for continuous phase transitions, which shows that the spin structure alone can break spatial inversion symmetry leading to ferroelectric order. This phenomenological theory explains our experimental observation that the spontaneous polarization is restricted to lie along the crystal b axis and predicts that the magnitude should be proportional to a magnetic order parameter.

446 citations

Journal ArticleDOI
TL;DR: Very general symmetry considerations uniquely favor a bcc crystal structure near the melting line as discussed by the authors, which agrees with observations that almost all metals on the left-hand side of the periodic table are bcc at high temperature, and that even where other structures are more stable, the first phase nucleated on rapid cooling can be bcc.
Abstract: Very general symmetry considerations uniquely favor a bcc crystal structure near the melting line. This agrees with observations that almost all metals on the left-hand side of the periodic table are bcc at high temperature, and that, even where other structures are more stable, the first phase nucleated on rapid cooling can be bcc. Furthermore, icosahedral local symmetries are favored in amorphous solids. Fluctuation effects cause the transition from isotropic liquid to crystal to be first order in any dimension.

440 citations

Book
01 Oct 1988
TL;DR: In this article, the authors present a review of Thermodynamics Statistical Ensembles Mean Field and Landau Theory Dense Gases and Liquids Critical Phenomena I critical phenomena II: The Renormalization Group Simulations Polymers and Membranes Quantum Fluids Linear Response Theory Disordered Materials
Abstract: Review of Thermodynamics Statistical Ensembles Mean Field and Landau Theory Dense Gases and Liquids Critical Phenomena I Critical Phenomena II: The Renormalization Group Simulations Polymers and Membranes Quantum Fluids Linear Response Theory Disordered Materials.

436 citations

Journal ArticleDOI
TL;DR: In this article, the authors evaluated the properties of magnetometers with the framework of the Landau theory for the second order phase transition or the thermodynamics in magnetic fields, and compared the results with direct experimental results as well as those obtained using the molecular field model.
Abstract: Magnetic refrigeration, an emerging new technology for cooling and gas liquefaction, needs magnetic materials with specific thermomagnetic behavior. Depending on the thermodynamic cycle selected, the isothermal magnetic entropy change or the adiabatic temperature change upon field application needs to be a preselected function of temperature. To obtain these properties, most designers rely on calorimetry, an expensive and time consuming technique. The present article describes that, classical magnetic measurements, when evaluated within the framework of the Landau theory for the second order phase transition or the thermodynamics in magnetic fields, are able to provide the preliminary information needed for the design of magnetic refrigerators. After reviewing the theory, experimental results on ferromagnetic gadolinium (Gd) and helimagnetic dysprosium (Dy) are analyzed and compared to direct experimental results as well as to those obtained using the molecular field model. The results demonstrate the reproducibility of entropy calculations and the good agreement between the experimental and the calculated specific heat anomalies. While the molecular field theory which assumes simple ferromagnetic order clearly fails for helimagnetic dysprosium, an analysis of the experimental data based on the Landau theory gives reliable results. Besides, the field and temperature dependencies of the isothermal magnetic entropy change allows one to characterize the magnetic structure (nature of the magnetic order) of the sample. Furthermore, magnetic measurements define the useful field range and provide information on transitions that influence the thermal behavior and magnetic losses.

360 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202317
202242
202142
202041
201949
201855