Question

Calculate (a) the saturation magnetization and (b) the saturation flux density for nickel, which has a density of 8.90 g/cm3. Solve by deriving the various equations step-by-step

Answer 1

The maximum possible magnetization, or magnetic saturation, M_s of a ferromagnetic material represents the magnetization that results when all the magnetic dipoles in a solid piece are mutually aligned to the external field.There is a corresponding saturation flux density B_s.

The saturation magnetization is equal to the product of the net magnetic moment for each atom and the number of atoms present. For nickel, the net magnetic moment per atom is 0.60 Bohr magnetrons.

The most fundamental magnetic moment is the Bohr magnetron, μ_B

μ_B = 9.27 x 10^-24 A-m²

Part a)

M_s = 0.60μ_BN

N = ρN_A/A_Ni ρ = density, NA = Avogadro constant and A = Molar mass of Nickel

      = (8.90 g/cm³)*(6.023 x 10²³ atoms/mol)/58.71 g/mol

    = 9.13 x 10²⁸ atoms/m³

M_s = 0.60 x (9.27 x 10^-24) x (9.13 x 10²⁸)

      = 5.1 x 10⁵ A/m

Part b)

B_s = μ_oM_s = 4π x 10^-7 H/m x 5.1 x 10⁵ A/m = 0.64 Tesla

Where μ_o isPermeability of a vacuum

μ_o = 4π x 10^-7 (1.257 x 10^-6) H/m or T-m/A

Units:                   T: Tesla

1T = 1 V-s/m²