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Nanoscale Magnetism
| Content Provider | Scilit |
|---|---|
| Author | Kukreja, Roopali Ohldag, Hendrik |
| Copyright Year | 2020 |
| Description | Book Name: 21st Century Nanoscience – A Handbook |
| Abstract | Magnetism in materials is one of the fundamental physical phenomena that have been employed in applications like compasses for centuries. Ferromagnetic materials have been used in various applications throughout the history of mankind. Aristotle is attributed to having the first scientific discussion on magnetism with Thales of Miletus around 585 B.C. [1]. Around the same time, in ancient India, Sushruta, a surgeon, used magnet for surgical purposes for the first time. [2]. In ancient China, the earliest literary reference to magnetism lies in a book of the 4th century BC named after its author, The Master of Demon Valley [3]. By the 12th century, medieval Chinese navigators were using magnetic materials in compass needles for navigation. However, the fundamental phenomena underlying magnetic order were only recently understood after the advent of quantum mechanics in the 20th century, and it revolves around the property of electron called ‘spin’. In the early 20th century, Weiss used the concept of ‘molecular field’ which aligns the spins present in a ferromagnetic material and is responsible for long-range magnetic ordering [4], although the origin of this field and its huge magnitude could not be explained. It was with the development of symmetrization postulate classifying electrons as Fermions, which manifested as exchange interaction between electrons provided the field necessary to achieve ferromagnetic ordering. It should be noted that the exchange interaction is a purely quantum mechanical concept originating from the fact that the electrons are Fermions following Pauli’s Exclusion Principle [5]. This ‘exchange field’ defines the spin system in a material and is responsible for the spin alignment, either ferromagnetic or antiferromagnetic. On the other hand, on a macroscopic scale, magnetism was believed to be fully understood after the publication of Maxwell’s laws and theory of electromagnetism, and magnetism research therefore attracted mainly the interest of engineers rather than physicists. This changed dramatically with the advent of vacuum technology, which allowed controlled thin-film growth on the monolayer scale resulting in well-defined growth of magnetic thin films, surfaces and interfaces. Consequently, nanoscale magnetism became highly relevant for magnetic storage technologies in the 1960s. With the discovery of many interesting interfacial phenomenon such as giant magnetoresistance (GMR), spin injection, spin transfer torque (STT), spin pumping etc., fundamental magnetism research has undergone a magnifi-cent revival in past 50 years. |
| Related Links | https://content.taylorfrancis.com/books/download?dac=C2017-0-65604-4&isbn=9780429347313&doi=10.1201/9780429347313-17&format=pdf |
| DOI | 10.1201/9780429347313-17 |
| Language | English |
| Publisher | Informa UK Limited |
| Publisher Date | 2020-04-02 |
| Access Restriction | Open |
| Subject Keyword | Book Name: 21st Century Nanoscience – A Handbook History and Philosophy of Science Materials Ferromagnetic Material Fundamental Century Advent |
| Content Type | Text |
| Resource Type | Chapter |
