Indirect interactions between magnetic nanoparticles in granular alloys

Abstract An extension of the RKKY mechanism is obtained for indirect magnetic interaction between nanogranules of magnetic metal in non-magnetic metallic matrix. The coherent scattering by all the spins in a granule essentially modifies the common RKKY law for point-like magnetic scatterers. In 3D system, the magnitude of RKKY oscillations is strongly suppressed, due to coherent narrowing of scattering angle to ∼1/( k F r 0 ) 2 . No such strong suppression occurs for the 2D analog of this system, in-plane magnetized discs over a 2DEG layer, but the RKKY period and the spatial decay law are modified.