title: Magnetic coupling at rare earth ferromagnet/transition metal ferromagnet interfaces: A comprehensive study of Gd/Ni.
abstract: Thin film magnetic heterostructures with competing interfacial coupling and Zeeman energy provide a fertile ground to study phase transition between different equilibrium states as a function of external magnetic field and temperature. A rare-earth (RE)/transition metal (TM) ferromagnetic multilayer is a classic example where the magnetic state is determined by a competition between the Zeeman energy and antiferromagnetic interfacial exchange coupling energy. Technologically, such structures offer the possibility to engineer the macroscopic magnetic response by tuning the microscopic interactions between the layers. We have performed an exhaustive study of nickel/gadolinium as a model system for understanding RE/TM multilayers using the element-specific measurement technique x-ray magnetic circular dichroism, and determined the full magnetic state diagrams as a function of temperature and magnetic layer thickness. We compare our results to a modified Stoner-Wohlfarth-based model and provide evidence of a thickness-dependent transition to a magnetic fan state which is critical in understanding magnetoresistance effects in RE/TM systems. The results provide important insight for spintronics and superconducting spintronics where engineering tunable magnetic inhomogeneity is key for certain applications.
authors.affiliation: Department of Materials Science and Metallurgy, University of Cambridge, CB3 0FS, Cambridge, United Kingdom.
authors.forename: T D C
authors.initials: TD
authors.lastname: Higgs
authors.affiliation: Department of Physics, Stanford University, Stanford, CA 94305, USA.
authors.forename: S
authors.initials: S
authors.lastname: Bonetti
authors.affiliation: SLAC National Accelerator Laboratory, California 94025, USA.
authors.forename: H
authors.initials: H
authors.lastname: Ohldag
authors.affiliation: Department of Materials Science and Metallurgy, University of Cambridge, CB3 0FS, Cambridge, United Kingdom.|Department of Physics, Loughborough University, Loughborough, LE11 3TU, United Kingdom.
authors.forename: N
authors.initials: N
authors.lastname: Banerjee
authors.affiliation: State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China.
authors.forename: X L
authors.initials: XL
authors.lastname: Wang
authors.affiliation: Stanford Institute for Materials and Energy Science, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.|Department of Applied Physics, Stanford University, Stanford, California 94305, USA.
authors.forename: A J
authors.initials: AJ
authors.lastname: Rosenberg
authors.affiliation: Department of Materials Science and Metallurgy, University of Cambridge, CB3 0FS, Cambridge, United Kingdom.
authors.forename: Z
authors.initials: Z
authors.lastname: Cai
authors.affiliation: State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China.
authors.forename: J H
authors.initials: JH
authors.lastname: Zhao
authors.affiliation: Stanford Institute for Materials and Energy Science, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.|Department of Applied Physics, Stanford University, Stanford, California 94305, USA.
authors.forename: K A
authors.initials: KA
authors.lastname: Moler
authors.affiliation: Department of Materials Science and Metallurgy, University of Cambridge, CB3 0FS, Cambridge, United Kingdom.
authors.forename: J W A
authors.initials: JW
authors.lastname: Robinson