1)The curie temperature of iron is 1043 Kelvin. Assume that iron atoms, when in metallic form have moments of 2 Bohr magneton per atom. Iron is body centered cube with lattice parameter a = 0.286 nm. Calculate the curie constant.

I solved it in the following way:

Let m be the magnetic moment of an iron atom, N be the number of atoms per unit volume, K be the boltzmann constant, mu be the permeability of free space and C be the Curie constant.

m = 2[m(B)] {where m(B) is Bohr magneton}

= 18.54 x 10^(-24) A-m^2

N = n/(a^3) {where n is number of atoms in 1 cubic lattice of iron}

= 2/[(0.286 x 10^(-9))^3]

= 8.5 x 10^28 atoms per unit volume

C = [(m^2)(mu)N]/[3K]

C = 0.89

But the answer given in my book is 0.66.