Van belang voor de spoelen en de metalen kern is de 4e kolom: μ/μ0
In de formule B=μr*μ0*H (μ=μr*μ0 of te wel: μr=μ/μ0
Dus hoe groter μr hoe groter het magneetveld bij dezelfde H!
| Medium | Susceptibility χm (volumetric SI) | Permeability μ [H/m] | Relative Permeability μ/μ0 | Magnetic field | Frequency max. |
|---|---|---|---|---|---|
| Metglas | 1.25 | 1,000,000[7] | at 0.5 T | 100 kHz | |
| Nanoperm | 10×10−2 | 80,000[8] | at 0.5 T | 10 kHz | |
| Mu-metal | 2.5×10−2 | 20,000[9] | at 0.002 T | ||
| Mu-metal | 50,000[10] | ||||
| Cobalt-Iron (high permeability strip material) | 18,000[11] | ||||
| Permalloy | 8,000 | 1.0×10−2 | 8,000[9] | at 0.002 T | |
| Electrical steel | 5.0×10−3 | 4,000[9] | at 0.002 T | ||
| Ferritic Stainless Steel (annealed) | 1000 – 1800[12] | ||||
| Martensitic Stainless Steel (annealed) | 750 – 950[12] | ||||
| Ferrite (manganese zinc) | >8.0×10−4 | 640 (or more) | 100 kHz ~ 1 MHz | ||
| Ferrite (nickel zinc) | 2.0×10−5 – 8.0×10−4 | 16–640 | 100 kHz ~ 1 MHz[citation needed] | ||
| Carbon Steel | 8.75×10−4 | 100[9] | at 0.002 T | ||
| Nickel | 1.25×10−4 | 100[9] – 600 | at 0.002 T | ||
| Martensitic Stainless Steel (hardened) | 40 – 95[12] | ||||
| Austenitic Stainless Steel | 1.003 – 7 [13][12] [note 1] | ||||
| Neodymium magnet | 1.05[14] | ||||
| Platinum | 1.2569701×10−6 | 1.000265 | |||
| Aluminum | 2.22×10−5[15] | 1.2566650×10−6 | 1.000022 | ||
| Wood | 1.00000043[15] | ||||
| Air | 1.2566375×10−6 | 1.00000037 [16] | |||
| Concrete (dry) | 1[17] | ||||
| Vacuum | 0 | π4×10−7 (μ0) | 1[18] | ||
| Hydrogen | −2.2×10−9[15] | 1.2566371×10−6 | 1.0000000 | ||
| Teflon | 1.2567×10−6[9] | 1.0000 | |||
| Sapphire | −2.1×10−7 | 1.2566368×10−6 | 0.99999976 | ||
| Copper | −6.4×10−6 or −9.2×10−6[15] | 1.2566290×10−6 | 0.999994 | ||
| Water | −8.0×10−6 | 1.2566270×10−6 | 0.999992 | ||
| Bismuth | −1.66×10−4 | 0.999834 | |||
| Superconductors | −1 | 0 | 0 |