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Amorphous magnet

In physics, amorphous magnet refers to a magnet made from amorphous solids. Below a certain temperature, these magnets present permanent magnetic phases produced by randomly located magnetic moments.[1] Three common types of amorphous magnetic phases are asperomagnetism, speromagnetism and sperimagnetism, which correspond to ferromagnetism, antiferromagnetism and ferrimagnetism, respectively, of crystalline solids. Spin glass models can present these amorphous types of magnetism.[2] Due to random frustration, amorphous magnets possess many nearly degenerate ground states.[1]

Schematic representation of a crystalline ferromagnetic phase (top) and a disordered phase of an amorphous magnet (bottom)

The terms for the amorphous magnetic phases were coined by Michael Coey in 1970s.[2][3][4] The Greek root spero/speri (Greek: διασπειρω, romanizeddiaspeiro) means 'to scatter'.[1][4][a]

Phases edit

Single species edit

Asperomagnetism edit

Asperomagnetism is the equivalent of ferromagnetism for a disordered system with random magnetic moments. It is defined by short range correlations of locked magnetic moments within small noncrystalline regions, with average long range correlations. Speromagnets possess a permanent net magnetic moment.[2]

An example of a asperomagnets is amorphous YFe3 and DyNi3.[2][5]

Speromagnetism edit

Speromagnetism is the equivalent of antiferromagnetism for a disordered system with random magnetic moments. It is defined by short range correlations of locked magnetic moments within small noncrystalline regions, without average long range correlations. Speromagnets do not have a net magnetic moment.[2]

An example of a solid presenting speromagnetism is amorphous YFe2 and can be detected using Mössbauer spectroscopy.[2][5]

Multiple species edit

Sperimagnetism edit

Sperimagnetism is the equivalent of ferrimagnetism for a disordered system with two or more species of magnetic moments, with at least one species locked in random magnetic moments.[1][6] Sperimagnets possess a permanent net magnetic moment.[6] When all species are the same, this phase is equivalent to asperomagnetism.[6]

Notes edit

  1. ^ Sperimagnetism was coined in 1973 by Coey and P.W. Reinhard, but was later relabelled to speromagnetism.[4]

References edit

  1. ^ a b c d Coey, J. M. D. (2010-03-25). Magnetism and Magnetic Materials. Cambridge University Press. ISBN 978-1-139-48692-7.
  2. ^ a b c d e f Kaneyoshi, Takahito (2018-01-18). Amorphous Magnetism. CRC Press. ISBN 978-1-351-07806-1.
  3. ^ Memoir. The Society. 1963. ISBN 978-81-85867-05-2.
  4. ^ a b c Coey, J. M. D. (1978-03-01). "Amorphous magnetic order". Journal of Applied Physics. 49 (3): 1646–1652. Bibcode:1978JAP....49.1646C. doi:10.1063/1.324880. ISSN 0021-8979.
  5. ^ a b Long, G. J.; Grandjean, F. (2013-06-29). Mössbauer Spectroscopy Applied to Magnetism and Materials Science. Springer Science & Business Media. ISBN 978-1-4899-2409-4.
  6. ^ a b c Hurd, C. M. (1982). "Varieties of magnetic order in solids". Contemporary Physics. 23 (5): 469–493. Bibcode:1982ConPh..23..469H. doi:10.1080/00107518208237096. ISSN 0010-7514.

amorphous, magnet, physics, amorphous, magnet, refers, magnet, made, from, amorphous, solids, below, certain, temperature, these, magnets, present, permanent, magnetic, phases, produced, randomly, located, magnetic, moments, three, common, types, amorphous, ma. In physics amorphous magnet refers to a magnet made from amorphous solids Below a certain temperature these magnets present permanent magnetic phases produced by randomly located magnetic moments 1 Three common types of amorphous magnetic phases are asperomagnetism speromagnetism and sperimagnetism which correspond to ferromagnetism antiferromagnetism and ferrimagnetism respectively of crystalline solids Spin glass models can present these amorphous types of magnetism 2 Due to random frustration amorphous magnets possess many nearly degenerate ground states 1 Schematic representation of a crystalline ferromagnetic phase top and a disordered phase of an amorphous magnet bottom The terms for the amorphous magnetic phases were coined by Michael Coey in 1970s 2 3 4 The Greek root spero speri Greek diaspeirw romanized diaspeiro means to scatter 1 4 a Contents 1 Phases 1 1 Single species 1 1 1 Asperomagnetism 1 1 2 Speromagnetism 1 2 Multiple species 1 2 1 Sperimagnetism 2 Notes 3 ReferencesPhases editSingle species edit Asperomagnetism edit Asperomagnetism is the equivalent of ferromagnetism for a disordered system with random magnetic moments It is defined by short range correlations of locked magnetic moments within small noncrystalline regions with average long range correlations Speromagnets possess a permanent net magnetic moment 2 An example of a asperomagnets is amorphous YFe3 and DyNi3 2 5 Speromagnetism edit Speromagnetism is the equivalent of antiferromagnetism for a disordered system with random magnetic moments It is defined by short range correlations of locked magnetic moments within small noncrystalline regions without average long range correlations Speromagnets do not have a net magnetic moment 2 An example of a solid presenting speromagnetism is amorphous YFe2 and can be detected using Mossbauer spectroscopy 2 5 Multiple species edit Sperimagnetism edit Sperimagnetism is the equivalent of ferrimagnetism for a disordered system with two or more species of magnetic moments with at least one species locked in random magnetic moments 1 6 Sperimagnets possess a permanent net magnetic moment 6 When all species are the same this phase is equivalent to asperomagnetism 6 Notes edit Sperimagnetism was coined in 1973 by Coey and P W Reinhard but was later relabelled to speromagnetism 4 References edit a b c d Coey J M D 2010 03 25 Magnetism and Magnetic Materials Cambridge University Press ISBN 978 1 139 48692 7 a b c d e f Kaneyoshi Takahito 2018 01 18 Amorphous Magnetism CRC Press ISBN 978 1 351 07806 1 Memoir The Society 1963 ISBN 978 81 85867 05 2 a b c Coey J M D 1978 03 01 Amorphous magnetic order Journal of Applied Physics 49 3 1646 1652 Bibcode 1978JAP 49 1646C doi 10 1063 1 324880 ISSN 0021 8979 a b Long G J Grandjean F 2013 06 29 Mossbauer Spectroscopy Applied to Magnetism and Materials Science Springer Science amp Business Media ISBN 978 1 4899 2409 4 a b c Hurd C M 1982 Varieties of magnetic order in solids Contemporary Physics 23 5 469 493 Bibcode 1982ConPh 23 469H doi 10 1080 00107518208237096 ISSN 0010 7514 Retrieved from https en wikipedia org w index php title Amorphous magnet amp oldid 1195124953, wikipedia, wiki, book, books, library,

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