Soft magnetic materials, permeability & core loss reference sheet
This technical reference sheet details the physical parameters, operational limits, and Steinmetz core-loss coefficients across soft magnetic material classes. Cross-reference specific terminology in our electromagnetic coil design and winding glossary.
Soft magnetic material characteristics matrix
| Material class | Initial permeability ($\mu_i$) | Saturation flux density ($B_{\text{sat}}$) | Curie temp ($T_c$) | Primary application / key advantage |
|---|---|---|---|---|
| MnZn ferrites | 1,000 – 15,000 | 350 – 530 mT | > 200 °C | High-frequency transformers & inductors (10 kHz – 2 MHz). Learn more in the glossary under Ferrites. |
| NiZn ferrites | 100 – 1,500 | 250 – 400 mT | > 150 °C | High-frequency RF & EMI suppression (> 10 MHz) due to extremely high resistivity ($\rho$). |
| Sendust (Kool Mμ) | 26 – 125 | ~ 1,050 mT | > 500 °C | Power factor correction (PFC) chokes with soft-saturation behavior. See Sendust in the glossary. |
| Nanocrystalline | 20,000 – 100,000 | 1,200 – 1,300 mT | > 560 °C | Ultra-compact common-mode chokes and wideband transformers. Details in Nanocrystalline cores. |
| Mu-metals (Ni-Fe) | 80,000 – 200,000 | 700 – 800 mT | ~ 400 °C | Precision magnetic shielding and low-frequency sensor cores. Cross-link: Mu-metals entry. |
| Amorphous metals | 2,000 – 10,000 | 1,500 – 1,860 mT | > 350 °C | High-efficiency grid power conversion and pulsed-power systems. See Amorphous metals. |
Steinmetz core loss coefficients ($P_v = k \cdot f^\alpha \cdot B^\beta$)
Volumetric core loss ($P_v$, in $\text{kW/m}^3$) under sinusoidal excitation. Review mathematical foundations in our Steinmetz equation glossary term or explore operational strategies in our guide on preventing core saturation in high-current inductor design.
| Material grade | Frequency range ($f$) | Coefficient $k$ | Exponent $\alpha$ (freq) | Exponent $\beta$ (flux) |
|---|---|---|---|---|
| N87 (MnZn ferrite) | 25 – 100 kHz | 7.13 | 1.42 | 2.62 |
| N97 (MnZn ferrite) | 50 – 200 kHz | 4.82 | 1.51 | 2.71 |
| 3C95 (MnZn ferrite) | 20 – 150 kHz | 5.20 | 1.46 | 2.55 |
For further material processing rules, refer to our comprehensive guide on soft magnetic materials processing.
For standardized magnetic material specifications and testing methodologies, consult the IEC 60404 magnetic materials standards catalog.