# Magnetic vector potential

1. Jul 17, 2009

### zokomoko

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

A current loop (of circular shape) is located at the X-Y plane.
What is the magnetic field on the Z axis? (Use the magnetic moment and magnetic potential)

2. Relevant equations
M=(Ia)/c $$\widehat{z}$$

A=(MXr)/r$$^{3}$$

B=curl(A)

3. The attempt at a solution

I got that the magnetic potential's Z component is zero.
The magnetic potential's angular component is: -(Iar)/cr^3
The magnetic potential's radial component is: (Iar)/cr^3

But when I take the curl of A I get: (Ia/cr^3) $$\widehat{z}$$ , which is obviously not true.
I've gone over the calculations a few times, maybe there's something I'm missing.