1.
Denis Gorbunov wrote:
... It is correct in a sense that the low-field magnetization is (MEr-MCo) = 9 - 5 = 4 (magnetic moments are antiparallel), and the high field magnetization is (MEr + MCo) = 9 + 5 = 14 (magnetic moments are parallel).
Doesn't this mean you are dealing with an anti-ferrimagnet (as opposed to a ferrimagnet)?!! 
2. I was puzzled by why the B=0 value of magnetization found by Mathcad is 0, not 4. It seems this is a numerical problem. If you set the initial guess value of phi to -pi/2 you do get 4 for the magnetization at B = 0.
Alan
