Lecture

Magneto-optical Kerr Effect: Fundamentals and Applications

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In course

MSE-670: Advanced Microscopy for Magnetic Materials

Theoretical and practical expertise is gained about the microscopy of spin structures and magnetic configuiations down to the sub-nm length and sub-ns time scales such as transmission electron microscopy, x-ray and light scattering, magnetic dichroism, and ...

Description

This lecture covers the fundamentals of the Magneto-optical Kerr Effect (MOKE), including its microscopic origin, examples of different MOKE configurations, and the use of MOKE in ultrafast magnetization processes. The instructor explains the interaction between light and magnetism, the origin of MO effects, and the classification of MO effects. Additionally, the lecture delves into the use of MOKE in studying magnetic optical spectroscopy and imaging techniques, such as Magnetic Circular Dichroism (MCD) and Voigt effect. Various examples and applications of MOKE are discussed, highlighting its advantages and disadvantages in terms of spatial and depth resolution, time resolution, and information obtained about the electronic structure and magnetic moments of materials.

Instructors (4)

Thomas La Grange

Expertise Electron Microscopy, Aberration Correct Scanning Transmission Electron Microscopy, Electron Diffraction, Ultrafast Transmission Electron Microscopy, Electron Energy Loss Spectroscopy, Energy Dispersive Spectroscopy, Materials Science, High-speed deformation, Dislocation Dynamics, Skyrmionics, Martensitic Phase Transformation Theory, Solidification Expertise Electron Microscopy, Aberration Correct Scanning Transmission Electron Microscopy, Electron Diffraction, Ultrafast Transmission Electron Micro

Fabrizio Carbone

Birth 20/04/1976 Master degree: University of Pavia "optoelectronic engineering". September 2001. Reasearch scientist at Pirelli Labs, Milan Italy between September 2000 and August 2002. PhD in condensed matter physics from the University of Geneva, prof. van der Marel gorup. January 2007 Post doc in physical chemistry at Caltech in prof. Zewail`s group. March 2007-April 2009

Dirk Grundler

Phoebe Marie Tengdin

Official source

Ontological neighbourhood

Physics

Condensed matter physics: Phase transitions

Related concepts (32)

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.

Kerr effect

The Kerr effect, also called the quadratic electro-optic (QEO) effect, is a change in the refractive index of a material in response to an applied electric field. The Kerr effect is distinct from the Pockels effect in that the induced index change is directly proportional to the square of the electric field instead of varying linearly with it. All materials show a Kerr effect, but certain liquids display it more strongly than others. The Kerr effect was discovered in 1875 by Scottish physicist John Kerr.

Magnetization

In classical electromagnetism, magnetization is the vector field that expresses the density of permanent or induced magnetic dipole moments in a magnetic material. Movement within this field is described by direction and is either Axial or Diametric. The origin of the magnetic moments responsible for magnetization can be either microscopic electric currents resulting from the motion of electrons in atoms, or the spin of the electrons or the nuclei. Net magnetization results from the response of a material to an external magnetic field.

Magnetic susceptibility

In electromagnetism, the magnetic susceptibility (; denoted χ, chi) is a measure of how much a material will become magnetized in an applied magnetic field. It is the ratio of magnetization M (magnetic moment per unit volume) to the applied magnetizing field intensity H. This allows a simple classification, into two categories, of most materials' responses to an applied magnetic field: an alignment with the magnetic field, χ > 0, called paramagnetism, or an alignment against the field, χ < 0, called diamagnetism.

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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