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POINTS TO BE CORRECTED IN CURRENT DAY MAGNETIC MATERIALS TEXTBOOKS.
Marcos De Campos1
1Federal Fluminense University, Volta Redonda, Brazil

PAPER: 520/SISAM/Regular (Oral) OS
SCHEDULED: 17:50/Wed. 23 Oct. 2024/Knossos

ABSTRACT:

The most used textbooks in the area of magnetic materials remain Chikazumi [1] and its north-american counterpart, Cullity [2].

Even these books are essentially correct, there are some needed corrections, also because these books are more than 50 years old, and some advances happened in this period. Some necessary corrections and amendments have been discussed in recent papers [3,4,5].

The most relevant correction is the description of exchange energy term, and also the nature and structure of the domain wall. The Bloch wall [6] is wrong . As consequence, there is no magnetic reversal by curling, which also has to be removed from textbooks [4].

The concept of heat in energy losses has also been discussed recently, and also the nature of the dissipative processes in a hysteresis cycle [5]. 

The Jiles-Atherton model lacks physical basis [7]. The hysteresis can be interpreted geometrically, as discussed recently [7].  The origin of Magnetic Barkhausen Noise has also  been clarified recently [8].

Coercivity mechanism in Sm-Co magnets of the 2:17 type were clarified [9], and should be inserted in the textbooks.

 

REFERENCES:
[1] https://global.oup.com/academic/product/physics-of-ferromagnetism-9780199564811
[2] https://onlinelibrary.wiley.com/doi/book/10.1002/9780470386323
[3] https://www.mdpi.com/2075-4701/14/8/866
[4] https://sciendo.com/article/10.2478/adms-2020-0002
[5] https://appol.ifpan.edu.pl/index.php/appa/article/view/146_34
[6] https://www.sciencedirect.com/science/article/abs/pii/S0304885317303219
[7] https://appol.ifpan.edu.pl/index.php/appa/article/view/146_20
[8] http://przyrbwn.icm.edu.pl/APP/PDF/136/app136z5p14.pdf
[9] https://www.teses.usp.br/teses/disponiveis/3/3133/tde-19072013-162250/pt-br.php