text: Formula for effective permeability of mixtures has a form 
  Here  is effective relative complex permeability of the mixture,  is relative complex permeability of the background medium containing small spherical inclusions of relative permeability  with volume fraction of . This formula was derived in dipole approximation. Magnetic octupole mode and all other magnetic oscillation modes of odd orders were neglected here. When  and  this formula has a simple form