Editing Permeability (electromagnetism) (section)

== Values for some common materials ==
The following table should be used with caution as the permeability of ferromagnetic materials varies greatly with field strength and specific composition and fabrication. For example, 4% electrical steel has an initial relative permeability (at or near 0&nbsp;T) of 2,000 and a maximum of 38,000 at T = 1 <ref name="kaye-laby">G.W.C. Kaye & T.H. Laby, Table of Physical and Chemical Constants, 14th ed, Longman, "Si Steel"</ref><ref>https://publikationen.bibliothek.kit.edu/1000066142/4047647 for the 38,000 figure 5.2</ref> and different range of values at different percent of Si and manufacturing process, and, indeed, the relative permeability of any material at a sufficiently high field strength trends toward 1 (at magnetic saturation).
{| class="wikitable sortable"
|+ Magnetic susceptibility and permeability data for selected materials
|-
! Medium
! class="unsortable"      | Susceptibility,<br/>volumetric, SI, ''χ''<sub>m</sub>
! data-sort-type="number" | Relative permeability, <br />{{abbr|max.|maximum}}, ''μ''/''μ''<sub>0</sub>
! class="unsortable"      | Permeability, <br/>''μ'' (H/m)
! class="unsortable"      | Magnetic <br/>field
! class="unsortable"      | Frequency, {{abbr|max.|maximum}}
|-
| [[Vacuum]]
| 0
| 1, exactly<ref>by definition</ref>
| {{physconst|mu0|round=9|unit=no|ref=no}}
|
|
|-
| [[Metglas]] 2714A (annealed)
|
| {{val|1000000}}<ref name="Metglas">{{cite web |url=http://www.metglas.com/products/page5_1_2_6.htm |title="Metglas Magnetic Alloy 2714A", ''Metglas'' |publisher=Metglas.com |access-date=2011-11-08 |url-status=dead |archive-url=https://web.archive.org/web/20120206100947/http://www.metglas.com/products/page5_1_2_6.htm |archive-date=2012-02-06 }}</ref>
| {{val|1.26|e=0}}
| At 0.5 T
| 100&nbsp;kHz
|-
| [[Iron]] (99.95% pure Fe annealed in H)
|
| {{val|200000}}<ref name="Iron">{{cite web|url=http://hyperphysics.phy-astr.gsu.edu/hbase/tables/magprop.html#c2 |title="Magnetic Properties of Ferromagnetic Materials", ''Iron'' |publisher=C.R Nave Georgia State University |access-date=2013-12-01}}</ref>
| {{val|2.5|e=-1}}
|
|
|-
| [[Permalloy]]
|
| {{val|100000}}<ref name="Jiles">{{cite book
| last = Jiles 
| first = David
| title = Introduction to Magnetism and Magnetic Materials
| publisher = CRC Press 
| year = 1998
| page= 354
| url = https://books.google.com/books?id=axyWXjsdorMC&q=mu+metal&pg=PA354
| isbn = 978-0-412-79860-3}}</ref>
| {{val|1.25|e=-1}}
| At 0.002 T
|
|-
| [https://web.archive.org/web/20200805140106/https://www.magnetec.de/en/materials-products/ NANOPERM®]
|
| {{val|80000}}<ref name="Nanoperm">{{cite web|url=http://www.magnetec.de/eng/pdf/werkstoffkennlinien_nano_e.pdf |title="Typical material properties of NANOPERM", ''Magnetec'' |access-date=2011-11-08}}</ref>
| {{val|1.0|e=-1}}
| At 0.5 T
| 10&nbsp;kHz
|-
| [[Mu-metal]]
|
| {{val|50000}}<ref name="nickal">{{cite web|url=http://www.nickel-alloys.net/nickelalloys.html |title=Nickel Alloys-Stainless Steels, Nickel Copper Alloys, Nickel Chromium Alloys, Low Expansion Alloys |publisher=Nickel-alloys.net |access-date=2011-11-08}}</ref>
| {{val|6.3|e=-2}}
|
|
|-
| [[Mu-metal]]
|
| {{val|20000}}<ref name="hyper">{{cite web|url=http://hyperphysics.phy-astr.gsu.edu/hbase/solids/ferro.html |title="Relative Permeability", ''Hyperphysics'' |publisher=Hyperphysics.phy-astr.gsu.edu |access-date=2011-11-08}}</ref>
| {{val|2.5|e=-2}}
| At 0.002 T
|
|-
| Cobalt-iron <br />(high permeability strip material)
|
| {{val|18000}}<ref name="vacuumschmeltze">{{cite web |url=http://www.vacuumschmelze.com/fileadmin/Medienbiliothek_2010/Downloads/HT/2013-03-27_Soft_Magnetic_Cobalt-_Iron_Alloys_final_version.pdf |title="Soft Magnetic Cobalt-Iron Alloys", ''Vacuumschmeltze'' |publisher=www.vacuumschmeltze.com |access-date=2013-08-03 |url-status=dead |archive-url=http://arquivo.pt/wayback/20160523203358/http%3A//www.vacuumschmelze.com/fileadmin/Medienbiliothek_2010/Downloads/HT/2013%2D03%2D27_Soft_Magnetic_Cobalt%2D_Iron_Alloys_final_version.pdf |archive-date=2016-05-23 }}</ref>
| {{val|2.3|e=-2}}
|
|
|-
| [[Iron]] (99.8% pure)
|
| {{val|5000}}<ref name="Iron" />
| {{val|6.3|e=-3}}
|
|
|-
| [[Electrical steel]]
|
| 2000 – 38000<ref name="kaye-laby"/><ref name="ellingson">{{cite web |url=https://eng.libretexts.org/Bookshelves/Electrical_Engineering/Electro-Optics/Book%3A_Electromagnetics_II_(Ellingson)/11%3A_Constitutive_Parameters_of_Some_Common_Materials/11.02%3A_Permeability_of_Some_Common_Materials |title="Permeability of Some Common Materials"|date=2 April 2020 | access-date=2022-12-09 }}</ref><ref>https://publikationen.bibliothek.kit.edu/1000066142/4047647 for 38000 at 1&nbsp;T figure 5.2</ref>
| {{val|5.0|e=-3}}
| At 0.002 T, 1 T
|
|-
| [[Stainless steel#Types|Ferritic stainless steel]] (annealed)
|
| 1000 – 1800<ref name="Carpenter">{{cite web|url=https://www.cartech.com/en/alloy-techzone/technical-information/technical-articles/magnetic-properties-of-stainless-steels|title=Magnetic Properties of Stainless Steels|year=2013|publisher=Carpenter Technology Corporation|author=Carpenter Technology Corporation}}</ref>
| {{val|1.26|e=-3}} – {{val|2.26|e=-3}}
|
|
|-
| [[Martensitic stainless steel]] (annealed)
|
| 750 – 950<ref name="Carpenter" />
| {{val|9.42|e=-4}} – {{val|1.19|e=-3}}
|
|
|-
| [[Ferrite (magnet)#Soft ferrites|Ferrite]] (manganese zinc)
|
| 350 – 20 000<ref>According to Ferroxcube (formerly Philips) Soft Ferrites data. https://www.ferroxcube.com/zh-CN/download/download/21</ref>
| {{val|4.4|e=-4}} – {{val|2.51|e=-2}}
| At 0.25 mT
| {{abbr|{{abbr|approx.|approximately}}|approximately}} 100&nbsp;Hz – 4&nbsp;MHz
|-
| [[Ferrite (magnet)#Soft ferrites|Ferrite]] (nickel zinc)
|
| 10 – 2300<ref>According to Siemens Matsushita SIFERRIT data. https://www.thierry-lequeu.fr/data/SIFERRIT.pdf</ref>
| {{val|1.26|e=-5}} – {{val|2.89|e=-3}}
| At ≤ 0.25 mT
| {{abbr|approx.|approximately}} 1&nbsp;kHz – 400&nbsp;MHz{{Citation needed|date=February 2012}}
|-
| [[Ferrite (magnet)#Soft ferrites|Ferrite]] (magnesium manganese zinc)
|
| 350 – 500<ref>According to PRAMET Šumperk fonox data. https://www.doe.cz/wp-content/uploads/fonox.pdf</ref>
| {{val|4.4|e=-4}} – {{val|6.28|e=-4}}
| At 0.25 mT
|
|-
| [[Ferrite (magnet)#Soft ferrites|Ferrite]] (cobalt nickel zinc)
|
| 40 – 125<ref>According to Ferronics Incorporated data. http://www.ferronics.com/catalog/ferronics_catalog.pdf</ref>
| {{val|5.03|e=-5}} – {{val|1.57|e=-4}}
| At 0.001 T
| {{abbr|approx.|approximately}} 2&nbsp;MHz – 150&nbsp;MHz
|-
| Mo-Fe-Ni powder compound <br />(molypermalloy powder, MPP)
|
| 14 – 550<ref>According to Magnetics MPP-molypermalloy powder data. https://www.mag-inc.com/Products/Powder-Cores/MPP-Cores</ref>
| {{val|1.76|e=-5}} – {{val|6.91|e=-4}}
|
| {{abbr|approx.|approximately}} 50&nbsp;Hz – 3&nbsp;MHz
|-
| Nickel iron powder compound
|
| 14 – 160<ref>According to MMG IOM Limited High Flux data. http://www.mmgca.com/catalogue/MMG-Sailcrest.pdf</ref>
| {{val|1.76|e=-5}} – {{val|2.01|e=-4}}
| At 0.001 T
| {{abbr|approx.|approximately}} 50&nbsp;Hz – 2&nbsp;MHz
|-
| Al-Si-Fe powder compound (Sendust)
|
| 14 – 160<ref>According to Micrometals-Arnold Sendust data. https://www.micrometalsarnoldpowdercores.com/products/materials/sendust</ref>
| {{val|1.76|e=-5}} – {{val|2.01|e=-4}}
|
| {{abbr|approx.|approximately}} 50&nbsp;Hz – 5&nbsp;MHz<ref>According to Micrometals-Arnold High Frequency Sendust data. https://www.micrometalsarnoldpowdercores.com/products/materials/sendust-high-frequency</ref>
|-
| Iron powder compound
|
| 14 – 100<ref>{{Cite web|url=https://micrometals.com/materials/pc|title=Micrometals Powder Core Solutions|website=micrometals.com|access-date=2019-08-17}}</ref>
| {{val|1.76|e=-5}} – {{val|1.26|e=-4}}
| At 0.001 T
| {{abbr|approx.|approximately}} 50&nbsp;Hz – 220&nbsp;MHz
|-
| Silicon iron powder compound
|
| 19 – 90<ref>According to Magnetics XFlux data. https://www.mag-inc.com/Products/Powder-Cores/XFlux-Cores</ref><ref>{{Cite web|url=https://micrometals.com/materials/200c|title=Micrometals Powder Core Solutions|website=micrometals.com|access-date=2019-08-18}}</ref>
| {{val|2.39|e=-5}} – {{val|1.13|e=-4}}
|
| {{abbr|approx.|approximately}} 50&nbsp;Hz – 40&nbsp;MHz
|-
| Carbonyl iron powder compound
|
| 4 – 35<ref>{{Cite web|url=https://www.micrometals.com/materials/rf|title=Micrometals Powder Core Solutions|website=www.micrometals.com|access-date=2019-08-17}}</ref>
| {{val|5.03|e=-6}} – {{val|4.4|e=-5}}
| At 0.001 T
| {{abbr|approx.|approximately}} 20&nbsp;kHz – 500&nbsp;MHz
|-
| [[Steel|Carbon steel]]
|
| {{val|100}}<ref name="hyper" />
| {{val|1.26|e=-4}}
| At 0.002 T
|
|-
| [[Nickel]]
|
| 100<ref name="hyper" /> – 600
| {{val|1.26|e=-4}} – {{val|7.54|e=-4}}
| At 0.002 T
|
|-
| [[Martensitic stainless steel]] (hardened)
|
| 40 – 95<ref name="Carpenter" />
| {{val|5.0|e=-5}} – {{val|1.2|e=-4}}
|
|
|-
| [[Stainless steel#Types|Austenitic stainless steel]]
|
| 1.003 – 1.05<ref name="Carpenter" /><ref name="SSAS">{{cite web|url=http://www.bssa.org.uk/cms/File/SSAS2.81-Magnetic%20Properties.pdf|title=Magnetic Properties of Stainless Steel|author=British Stainless Steel Association|publisher=Stainless Steel Advisory Service|year=2000}}</ref>{{efn|The permeability of austenitic stainless steel strongly depends on the history of mechanical strain applied to it, e.g. by [[cold forming|cold working]]}}
| {{val|1.260|e=-6}} – {{val|8.8|e=-6}}
|
|
|-
| [[Neodymium magnet]]
|
| 1.05<ref>{{cite book|url=https://books.google.com/books?id=_y3LSh1XTJYC&pg=PT232|page=232|title=Design of Rotating Electrical Machines|author1=Juha Pyrhönen |author2=Tapani Jokinen |author3=Valéria Hrabovcová |publisher=John Wiley and Sons|year=2009|isbn=978-0-470-69516-6}}</ref>
| {{val|1.32|e=-6}}
|
|
|-
| [[Platinum]]
|
| {{val|1.000265}}
| {{val|1.256970|e=-6}}
|
|
|-
| [[Aluminum]]
| {{val|2.22|e=-5}}<ref name="clarke">{{cite web|author=Richard A. Clarke |url=http://www.ee.surrey.ac.uk/Workshop/advice/coils/mu/ |title=Magnetic properties of materials, surrey.ac.uk |publisher=Ee.surrey.ac.uk |access-date=2011-11-08}}</ref>
| {{val|1.000022}}
| {{val|1.256665|e=-6}}
|
|
|-
| [[Wood]]
|
| {{val|1.00000043}}<ref name="clarke" />
| {{val|1.25663760|e=-6}}
|
|
|-
| [[Air]]
|
| {{val|1.00000037}}<ref name="Cullity2008">B. D. Cullity and C. D. Graham (2008), Introduction to Magnetic Materials, 2nd edition, 568 pp., p.16</ref>
| {{val|1.25663753|e=-6}}
|
|
|-
| [[Concrete]] (dry)
|
| 1<ref>{{cite web|author=NDT.net |url=http://www.ndt.net/article/ndtce03/papers/v078/v078.htm |title=Determination of dielectric properties of insitu concrete at radar frequencies |publisher=Ndt.net |access-date=2011-11-08}}</ref>
|
|
|
|-
| [[Hydrogen]]
| {{val|-2.2|e=-9}}<ref name="clarke" />
| {{val|1.0000000}}
| {{val|1.2566371|e=-6}}
|
|
|-
| [[Teflon]]
|
| {{val|1.0000}}
| {{val|1.2567|e=-6}}<ref name="hyper"/>
| 
|
|-
| [[Sapphire]]
| {{val|-2.1|e=-7}}
| {{val|0.99999976}}
| {{val|1.2566368|e=-6}}
|
|
|-
| [[Copper]]
| {{val|-6.4|e=-6}} or <br/>{{val|-9.2|e=-6}}<ref name="clarke" />
| {{val|0.999994}}
| {{val|1.256629|e=-6}}
|
|
|-
| [[Water]]
| {{val|-8.0|e=-6}}
| {{val|0.999992}}
| {{val|1.256627|e=-6}}
|
|
|-
| [[Bismuth]]
| {{val|-1.66|e=-4}}
| {{val|0.999834}}
| {{val|1.25643|e=-6}}
|
|
|-
| [[Pyrolytic carbon]]
|
| {{val|0.9996}}
| {{val|1.256|e=-6}}
|
|
|-
| [[Superconductor]]s
| −1
| 0
| 0
|
|
|}

[[File: Permeability of ferromagnet by Zureks.svg|thumb|Magnetisation curve for ferromagnets (and ferrimagnets) and corresponding permeability]]

A good [[Magnetic core#Magnetic core materials|magnetic core material]] must have high permeability.<ref>{{cite web|
url=http://www.ti.com/lit/ml/slup124/slup124.pdf|
title=Magnetics Design 2 – Magnetic Core Characteristics|
author=Dixon, L H|
publisher=Texas Instruments|
year=2001}}</ref>

For ''passive'' [[magnetic levitation]] a relative permeability below 1 is needed (corresponding to a negative susceptibility).

Permeability varies with a magnetic field. Values shown above are approximate and valid only at the magnetic fields shown. They are given for a zero frequency; in practice, the permeability is generally a function of the frequency. When the frequency is considered, the permeability can be [[Complex number|complex]], corresponding to the in-phase and out of phase response.