Induced magnetic moments of X (X=Sn, Au, Cu, Mo, Co) in thin Fe/Cr/X/Cr multilayers

• Published in: Physica. B, Condensed matter Vol. 334; no. 1; pp. 202 - 206
• Main Authors: Mukhopadhyay, Sanghamitra, Nguyen-Manh, Duc
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.06.2003; Elsevier
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Exact sciences and technology; Exchange and superexchange interactions; First principle calculations; Interfacial magnetic properties (multilayers, magnetic quantum wells, superlattices, magnetic heterostructures); Magnetic multilayer; Magnetic properties and materials; Magnetic properties of surface, thin films and multilayers; Magnetically ordered materials: other intrinsic properties; Physics; Proximity effect; Saturation moments and magnetic susceptibilities; TB-LMTO method; Magnetic multilayer; Proximity effect; TB-LMTO method; First principle calculations; Interfacial layer; Gold; Moessbauer effect; Digital simulation; Theoretical study; Magnetic moments; Iron; Molybdenum; Multilayers; Electronic structure; Polarized spin; Tight binding approximation; Atomic arrangement; Transition elements; Chromium; Copper; Exchange interactions; LMTO method
• ISSN: 0921-4526; 1873-2135
• DOI: 10.1016/S0921-4526(03)00065-6

The magnetic moment induced on a monolayer of X (X=Sn, Au, Cu, Mo, and Co) embedded in thin layers of Cr (designated as Fe/Cr/X/Cr) is investigated by first principle spin-polarized electronic structure calculations. We find that in the multilayers the X (X=Sn, Au, Mo) atoms get a small magnetic moment which is predominantly 5d (Sn,Au), or 4d (Mo) in character. This is induced by exchange interaction with 3d Cr orbitals at the Cr/X interfaces. Co and Cu atoms are weakly influenced by interfacial Cr. Fe layers reduce the magnetic moments of Cr atoms at the Cr/Sn interface, and so the induced magnetic moment on a Sn atom decreases from 0.067 μ B/atom in Cr/Sn to 0.044 μ B/atom in Fe/Cr/Sn/Cr. These results are in correlation with Mössbauer observations. The magnetic moment of a Cr atom depends strongly on the nature of the exchange interaction with its neighbours. Also, magnetic moments on Cr sites decrease smoothly away from the Fe layer for Sn, Au, Cu, and Mo, but not for Co. Then the magnetic moment increases abruptly at the Cr/X interface for X=Sn, Au, Cu, and Co, but not for Mo. The decrease in Cr magnetic moment is a result of dissimilar exchange interactions at Fe/Cr and Cr/X interfaces while its large increase at the Cr/X interface is a result of ferromagnetic coupling with X atomic layer and interface states arise due to dissimilar electronic environment around the Cr atomic layer at the interfaces.