# Calculation of curie constant

1. Jan 26, 2007

### Amith2006

1. The problem statement, all variables and given/known data

As none are responding to my query posted in Introductory Physics section, I am posting it here. Someone please guide me!!!
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.

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

3. The attempt at a solution

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.

2. Jan 26, 2007

### Dick

I suspect the difference is related to the phrase "body centered cube". Are you sure there are 2 atoms per lattice cube? I'd check around under subjects like "atomic packing factor" to make sure.

3. Jan 26, 2007

### Dick

On second thought the 2 seems ok. Hmm. I'm no expert in this field.

4. Jan 28, 2007

### Amith2006

What on earth is preventing you all from answering?????