title: Tunable room-temperature ferromagnet using an iron-oxide and graphene oxide nanocomposite.
abstract: Magnetic materials have found wide application ranging from electronics and memories to medicine. Essential to these advances is the control of the magnetic order. To date, most room-temperature applications have a fixed magnetic moment whose orientation is manipulated for functionality. Here we demonstrate an iron-oxide and graphene oxide nanocomposite based device that acts as a tunable ferromagnet at room temperature. Not only can we tune its transition temperature in a wide range of temperatures around room temperature, but the magnetization can also be tuned from zero to 0.011 A m(2)/kg through an initialization process with two readily accessible knobs (magnetic field and electric current), after which the system retains its magnetic properties semi-permanently until the next initialization process. We construct a theoretical model to illustrate that this tunability originates from an indirect exchange interaction mediated by spin-imbalanced electrons inside the nanocomposite.
authors.affiliation: 1] NUS Graduate School of Integrative Sciences and Engineering, National University of Singapore,28 Medical Drive, Singapore 117456 [2] Centre for Advanced 2D Materials and Graphene Research Centre, Faculty of Science, National University of Singapore, 6 Science Drive 2, Singapore 117546 [3] Department of Physics, Faculty of Science, National University of Singapore, 2 Science Drive 3, Singapore 117542.
authors.forename: Aigu L
authors.initials: AL
authors.lastname: Lin
authors.affiliation: 1] Centre for Advanced 2D Materials and Graphene Research Centre, Faculty of Science, National University of Singapore, 6 Science Drive 2, Singapore 117546 [2] Department of Physics, Faculty of Science, National University of Singapore, 2 Science Drive 3, Singapore 117542.
authors.forename: J N B
authors.initials: JN
authors.lastname: Rodrigues
authors.affiliation: 1] Centre for Advanced 2D Materials and Graphene Research Centre, Faculty of Science, National University of Singapore, 6 Science Drive 2, Singapore 117546 [2] Department of Chemistry, Faculty of Science, National University of Singapore, 3 Science Drive 3, Singapore 117543.
authors.forename: Chenliang
authors.initials: C
authors.lastname: Su
authors.affiliation: 1] Centre for Advanced 2D Materials and Graphene Research Centre, Faculty of Science, National University of Singapore, 6 Science Drive 2, Singapore 117546 [2] Department of Physics, Faculty of Science, National University of Singapore, 2 Science Drive 3, Singapore 117542.
authors.forename: M
authors.initials: M
authors.lastname: Milletari
authors.affiliation: 1] Centre for Advanced 2D Materials and Graphene Research Centre, Faculty of Science, National University of Singapore, 6 Science Drive 2, Singapore 117546 [2] Department of Chemistry, Faculty of Science, National University of Singapore, 3 Science Drive 3, Singapore 117543.
authors.forename: Kian Ping
authors.initials: KP
authors.lastname: Loh
authors.affiliation: Materials Science and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia.
authors.forename: Tom
authors.initials: T
authors.lastname: Wu
authors.affiliation: 1] Centre for Advanced 2D Materials and Graphene Research Centre, Faculty of Science, National University of Singapore, 6 Science Drive 2, Singapore 117546 [2] Department of Chemistry, Faculty of Science, National University of Singapore, 3 Science Drive 3, Singapore 117543.
authors.forename: Wei
authors.initials: W
authors.lastname: Chen
authors.affiliation: 1] Centre for Advanced 2D Materials and Graphene Research Centre, Faculty of Science, National University of Singapore, 6 Science Drive 2, Singapore 117546 [2] Department of Physics, Faculty of Science, National University of Singapore, 2 Science Drive 3, Singapore 117542.
authors.forename: A H Castro
authors.initials: AH
authors.lastname: Neto
authors.affiliation: 1] Centre for Advanced 2D Materials and Graphene Research Centre, Faculty of Science, National University of Singapore, 6 Science Drive 2, Singapore 117546 [2] Department of Physics, Faculty of Science, National University of Singapore, 2 Science Drive 3, Singapore 117542 [3] Yale-NUS College, 16 College Ave West, Singapore 138527.
authors.forename: Shaffique
authors.initials: S
authors.lastname: Adam
authors.affiliation: 1] NUS Graduate School of Integrative Sciences and Engineering, National University of Singapore,28 Medical Drive, Singapore 117456 [2] Centre for Advanced 2D Materials and Graphene Research Centre, Faculty of Science, National University of Singapore, 6 Science Drive 2, Singapore 117546 [3] Department of Physics, Faculty of Science, National University of Singapore, 2 Science Drive 3, Singapore 117542.
authors.forename: Andrew T S
authors.initials: AT
authors.lastname: Wee