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Progress in Ferromagnetism Research

Ferromagnetism is a form of magnetism that can be acquired in an external magnetic field and usually retained in its absence, so that ferromagnetic materials are used to make permanent magnets. A ferromagnetic material may therefore be said to have a high magnetic permeability and susceptibility (which depends upon temperature). Examples are iron, cobalt, nickel, and their alloys. Ultimately, ferromagnetism is caused by spinning electrons in the atoms of the material, which act as tiny weak magnets. They align parallel to each other within small regions of the material to form domains, or areas of stronger magnetism. In an unmagnetised material, the domains are aligned at random so there is no overall magnetic effect. If a magnetic field is applied to that material, the domains align to point in the same direction, producing a strong overall magnetic effect. Permanent magnetism arises if the domains remain aligned after the external field is removed. Ferromagnetic materials exhibit hysteresis. In 2004, it was discovered that a certain allotrope of carbon, nanofoam , exhibited ferromagnetism. The effect dissipates after a few hours at room temperature, but lasts longer at cold temperatures. The material is also a semiconductor. It is thought that other similarly formed materials, of boron and nitrogen, may also be ferromagnetic. This new book rings together leading research from throughout the world.

Magnetic Nano- and Microwires

Magnetic nanowires and microwires are key tools in the development ofenhanced devices for information technology (memory and data processing) andsensing. Offering the combined characteristics of high density, high speed, andnon-volatility, they facilitate reliable control of the motion of magnetic domainwalls; a key requirement for the development of novel classes of logic and storagedevices. Part One introduces the design and synthesis of magnetic nanowires andmicrowires, reviewing the growth and processing of nanowires and nanowireheterostructures using such methods as sol-gel and electrodepositioncombinations, focused-electron/ion-beam-induced deposition, chemicalvapour transport, quenching and drawing and magnetic interactions. Magneticand transport properties, alongside domain walls, in nano- and microwiresare then explored in Part Two, before Part Three goes on to explore a widerange of applications for magnetic nano- and microwire devices, includingmemory, microwave and electrochemical applications, in addition to thermalspin polarization and configuration, magnetocalorific effects and Bloch pointdynamics. - Detailed coverage of multiple key techniques for the growth and processing of nanowires and microwires - Reviews the principles and difficulties involved in applying magnetic nano- and microwires to a wide range of applications - Combines the expertise of specialists from around the globe to give a broad overview of current and future trends

Les Elémens de géométrie d'Euclide