1. Magnetization Curve:
* Initial Permeability: The relative permeability is high at low MMF, indicating a high initial susceptibility to magnetization.
* Saturation: As MMF increases, the relative permeability gradually decreases until it reaches saturation, where the material can no longer be further magnetized. The permeability at saturation is very low.
* Hysteresis: The relationship between MMF and relative permeability exhibits hysteresis, meaning the path taken when magnetizing and demagnetizing the material is not the same.
2. Temperature:
* Curie Temperature: Above a critical temperature known as the Curie temperature, ferromagnetic materials lose their ferromagnetic properties and become paramagnetic. Their permeability drops significantly above this point.
3. Domain Structure:
* Domain Walls: Within a ferromagnetic material, there are small regions called domains, each with its own magnetization direction. The movement of domain walls in response to MMF contributes to the material's permeability. This movement is not linear with MMF.
4. Other Factors:
* Stress and Strain: Mechanical stresses can also affect the permeability of a ferromagnetic material.
* Impurities and Defects: Impurities and crystal defects within the material can impede domain wall motion, affecting permeability.
Summary:
Instead of a direct relationship, the relative permeability of a ferromagnetic material is a function of its magnetization curve, temperature, domain structure, and other factors. It's important to note that:
* Relative permeability is not constant: It varies with MMF and other factors.
* Saturation limits permeability: There's a limit to how much magnetization a ferromagnetic material can achieve.
* Hysteresis influences permeability: The magnetization history of the material influences its permeability.
Therefore, while MMF is a crucial factor influencing magnetization, the relationship with relative permeability is not linear and is complex.
