2. Hard Magnetic Materials

Question 1

What are the requirements of hard magnets?

Answer 1

High coercivity (For ferromagnetic material the coercivity is the intensity of the applied magnetic field required to reduce the magnetization of that material to zero after the magnetization of the sample has been driven to saturation) and high BH(max)

Question 2

Why do permanent magnets have high coercivity?

Answer 2

Due to high density of domain wall pinning sites