Dependence of the interlayer coupling on the thickness of magnetic and outer nonmagnetic films

Dependence of the interlayer exchange coupling on the thickness of magnetic and outer nonmagnetic films in a magnetic sandwich covered on both sides by nonmagnetic films is analyzed within the quantum well model for perfectly reflecting boundary conditions at the outer surfaces. Two different cases are considered: (i) thickness of one of the two magnetic (outer nonmagnetic) films is constant, while the thickness of the second magnetic (outer nonmagnetic) film is varied, and (ii) both magnetic (outer nonmagnetic) films have equal thicknesses which vary simultaneously. It is shown that the oscillation periods corresponding to those two possibilities can be different, in general. It is also shown that the nonoscillatory component of the coupling parameter varies generally with the thickness of magnetic (outer nonmagnetic) films. © 1996 The American Physical Society.