Lecture

Ferromagnetism: Magnetic Properties

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In course

MSE-101(b): Materials:from chemistry to properties

Ce cours permet l'acquisition des notions essentielles relatives à la structure de la matière, aux équilibres et à la réactivité chimique en liaison avec les propriétés mécaniques, thermiques, électriques, magnétiques et optiques des matériaux. ...

Description

This lecture covers the magnetic properties of ferromagnetic materials, focusing on ferromagnetism and paramagnetism. It explains how ferromagnetic materials retain magnetization, creating a permanent magnetic field. The interaction of atomic moments and thermal agitation affecting magnetization are discussed, along with the concept of Curie temperature. The lecture also delves into hysteresis cycles in ferromagnetic materials, explaining saturation magnetization, residual magnetization, and energy loss. Additionally, it explores the applications of ferromagnetic materials in various industries.

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Instructors (4)

Fabien Sorin

Sep 2002-Oct 2007 Ph.D., Department of Materials Science and Engineering, MIT, USA. Supervisor: Prof. Yoel Fink; Thesis: Multi-material, Multifunctional Fiber Devices. After graduating with an engineering degree and a Master of Science in Physics from the Ecole Polytechnique in Palaiseau, France, Prof. Sorin joined the department of Materials Science and Engineering at the Massachusetts Institute of Technology (MIT) in Cambridge, USA for his graduate studies. He worked as a research assistant in the Photonic Bandgap Fibers and Devices Group of Professor Yoel Fink and graduated with a PhD in 2008. His PhD thesis led to the development of a new class of fiber material and devices and he was a pioneer of the field of multi-material fibers. Mar 2008-Oct 2010 Postdoctoral Associate and Research Scientist, Research Laboratory of Electronics, MIT. He then joined the Research Laboratory of Electronics at MIT as a Postdoctoral Associate, and continued as a Research Scientist associate, where he conducted independent research in the emerging field of multi-material fibers and was involved and led a variety of projects in fundamental research as well as in collaborations with local start-ups. Apr 2011 Feb 2013 Research Engineer, Saint-Gobain Recherche, Aubervilliers, France. Surface du Verre et interface Group In 2011, prof. Sorin returned to Europe and joined the company Saint-Gobain in the Saint-Gobain Recherche center, its biggest research center located near Paris in France. As a research engineer, he developed a new research thrust investigating new photonic materials and nanostructures for the energy and building industries. In particular, he and colleagues developed innovative processing approaches to deploy photonic nanostructures for light management over large area substrates, for applications in energy harvesting and saving, and for building materials and windows. Mar 2013 Present Assistant Professor tenure-track, Ecole Polytechnique Fédérale de Lausanne (EPFL), Switzerland. Head of the Photonic materials and fibre devices laboratory (FIMAP) Since March 2013, he is in the department of Materials Science (IMX) at the Ecole Polytechnique Fédérale de Lausanne (EPFL) as an assistant professor tenure-track. He is starting a research group on photonic materials and fiber devices (FIMAP), continuing on developing innovative materials processing approaches and photonic device architectures to develop new solutions in energy harvesting, saving and storage, in sensing and monitoring, health care and smart fabrics.

Roland Logé

Official source

Ontological neighbourhood

Physics

Condensed matter physics: Phase transitions

Related concepts (32)

Remanence

Remanence or remanent magnetization or residual magnetism is the magnetization left behind in a ferromagnetic material (such as iron) after an external magnetic field is removed. Colloquially, when a magnet is "magnetized", it has remanence. The remanence of magnetic materials provides the magnetic memory in magnetic storage devices, and is used as a source of information on the past Earth's magnetic field in paleomagnetism. The word remanence is from remanent + -ence, meaning "that which remains".

Paramagnetism

Paramagnetism is a form of magnetism whereby some materials are weakly attracted by an externally applied magnetic field, and form internal, induced magnetic fields in the direction of the applied magnetic field. In contrast with this behavior, diamagnetic materials are repelled by magnetic fields and form induced magnetic fields in the direction opposite to that of the applied magnetic field. Paramagnetic materials include most chemical elements and some compounds; they have a relative magnetic permeability slightly greater than 1 (i.

Curie temperature

In physics and materials science, the Curie temperature (TC), or Curie point, is the temperature above which certain materials lose their permanent magnetic properties, which can (in most cases) be replaced by induced magnetism. The Curie temperature is named after Pierre Curie, who showed that magnetism was lost at a critical temperature. The force of magnetism is determined by the magnetic moment, a dipole moment within an atom which originates from the angular momentum and spin of electrons.

Magnetic domain

A magnetic domain is a region within a magnetic material in which the magnetization is in a uniform direction. This means that the individual magnetic moments of the atoms are aligned with one another and they point in the same direction. When cooled below a temperature called the Curie temperature, the magnetization of a piece of ferromagnetic material spontaneously divides into many small regions called magnetic domains. The magnetization within each domain points in a uniform direction, but the magnetization of different domains may point in different directions.

Magnetic moment

In electromagnetism, the magnetic moment is the magnetic strength and orientation of a magnet or other object that produces a magnetic field. Examples of objects that have magnetic moments include loops of electric current (such as electromagnets), permanent magnets, elementary particles (such as electrons), composite particles (such as protons and neutrons), various molecules, and many astronomical objects (such as many planets, some moons, stars, etc).

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Michel Rappaz

After a PhD in solid state physics (1978) at the Ecole Polytechnique Fédérale de Lausanne (EPFL) and a post-doc at Oak Ridge National Laboratory, Michel Rappaz joined the Institute of Materials of EPFL in 1981. After two years in an engineering company, he came back to EPFL in 1984 where he was nominated Adjunct Professor in 1990 and Full Professor in 2003. He retired from EPFL in 2015 and is now Emeritus Professor and independent consultant for several industries and research centres. His main interests are in phase transformations and solidification, in particular the coupling of macroscopic aspects of heat and mass transfer with microscopic aspects of microstructure and defect formation. Among his diverse achievements, one can mention in particular the development of cellular automata for grain structure predictions and of granular models for hot tearing formation in castings, the coupling of Finite Element method with microscopic models of nucleation and growth, the application of the phase field method to the understanding of various microstructures, the discovery of quasicrystal mediated-nucleation in alloys, and many other studies both fundamental at the microstructure-defect level and more applied at the level of processes. Some of the software developments have been commercialized by a spin-off company founded by his group in 1991 (Calcom SA), now part of the French company ESI. Michel Rappaz initiated in 1992 an annual postgraduate course on solidification which has been attended by more than 900 participants from all over the world. He is presently collaborating closely with another spin-off company started from his group, Novamet SàrL. Michel Rappaz has received several awards, in particular the Mathewson co-author award (1994) and author award (1997) of the American Mineral, Metals and Materials Society (TMS), the Koerber foundation award jointly with Profs Y. Bréchet and M. Asbby (1996), the Sainte-Claire Deville Medal (1996) and the Grand Medal (2011) from the French Materials Society, the Bruce Chalmers Award of TMS (2002), the Mc Donald Memorial Lecture award of Canada (2005), the FEMS European Materials Gold Medal (2013) and the Brimacombe Prize of TMS (2015). He is a highly-cited author of ISI, a fellow of ASM, IOP and TMS, and has co-authored more than 200 publications and two books.

Related concepts (32)