A Ni-Cu alloy is prepared which has a lattice constant of 0.354 nm. The maximum magnetisation of the alloy is measured as 1.25*10^6 A/m. Assuming no interactions between Ni and Cu atoms, and the magnetisation comes from the all unpaired 3d Ni electrons.Estimate the wt. % Cu in the alloy. Both Ni and Cu have a fcc structure with 4 atoms in a unit cell.
Information given in the problem:
a = 0.354 nm = 0.354*10^-9 m,
Mmax = 1.25*10^6 A/m,
n = 4 (no. of atoms per unit cell)
Total no. of atoms (Cu + Ni) per cubic meter in Ni-Cu alloy will be,
N = n / [(Lattice constant)^3] = 4/(a^3)= 4/[(0.354*10^-9)^3] = 9.0167*10^28 atoms/m^3
1) No. of Cu and Ni atoms per cubic meter in in this Ni-Cu alloy
These are the equations used to solve this problem,
Net magnetic moments per atom (in Ni) = 0.60*Bohr Magneton = 0.60*uB ------(1)
This solution gives detailed knowledge of calculating number of atoms per unit cell of the alloy system. It comprised of step by step calculation method for mixed alloys. Students shall be able to understand and solve similar problems themselves after reviewing this solution thoroughly.