Mediaspace scheduled maintenance: Aug 25, 2026 07:00 - 12:00 AM. During this time, videos will be temporarily unavailable. Check status updates.

Lecture

Magnetostrictive Materials: AE Effect and Transducer Applications

In course

MSE-432: Introduction to magnetic materials in modern technologies

Interactive course addressing bulk and thin-film magnetic materials that provide application-specific functionalities in different modern technologies such as e.g. wind energy harvesting, electric article surveillance, spintronics, sensing, and data storag ...

Description

This lecture covers the AE effect in magnetostrictive materials, focusing on the variation of Young's modulus under magnetic fields. It also discusses transducer applications, such as Terfenol and Galfenols, for smart magnetostrictive metal usage in deep-sea measurements. The presentation delves into the historical development of magnetostrictive materials, including the discovery of Terfenol-D and Galfenol. Additionally, it explores the electronic article surveillance (EAS) device, detailing the optimization strategies in materials science and engineering for effective surveillance systems.

This video is available exclusively on Mediaspace for a restricted audience. Please log in to MediaSpace to access it if you have the necessary permissions.

Watch on Mediaspace

Instructor

Dirk Grundler

Official source

Ontological neighbourhood

Physics

Condensed matter physics: Phase transitions

Related concepts (32)

Magnetostriction

Magnetostriction (cf. electrostriction) is a property of magnetic materials that causes them to change their shape or dimensions during the process of magnetization. The variation of materials' magnetization due to the applied magnetic field changes the magnetostrictive strain until reaching its saturation value, λ. The effect was first identified in 1842 by James Joule when observing a sample of iron. This effect causes energy loss due to frictional heating in susceptible ferromagnetic cores.

Magnet

A magnet is a material or object that produces a magnetic field. This magnetic field is invisible but is responsible for the most notable property of a magnet: a force that pulls on other ferromagnetic materials, such as iron, steel, nickel, cobalt, etc. and attracts or repels other magnets. A permanent magnet is an object made from a material that is magnetized and creates its own persistent magnetic field. An everyday example is a refrigerator magnet used to hold notes on a refrigerator door.

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.

Coercivity

Coercivity, also called the magnetic coercivity, coercive field or coercive force, is a measure of the ability of a ferromagnetic material to withstand an external magnetic field without becoming demagnetized. Coercivity is usually measured in oersted or ampere/meter units and is denoted HC. An analogous property in electrical engineering and materials science, electric coercivity, is the ability of a ferroelectric material to withstand an external electric field without becoming depolarized.

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).

Related lectures (57)

Materials Science of Magnetic Materials

Covers the materials science of magnetic materials, focusing on properties, concepts, and optimization for functional applications.

Permanent Magnets: Hysteresis Cycle MOOC: Electromechanical conversion I

Covers the hysteresis cycle of permanent magnets and their sensitivity to temperature.

Ferromagnetism: Magnetic Properties

Explores the magnetic properties of ferromagnetic materials, including retention of magnetization and hysteresis cycles.

Dielectric and Magnetic Properties

Explores dielectric and magnetic properties of materials, including electrical conductivity, insulators, capacitors, and different types of magnetism.

Electronic Article Surveillance: Materials Optimization Log in to Mediaspace to watch this video