• Adam, Shaffique
• Neto, A. H. Castro
• Wee, Andrew T. S.
• Loh, Kian Ping
• Su, Chenliang
• Milletari, M.
• Lin, Aigu L.
• Chen, Wei
• Rodrigues, J. N. B.

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 m2/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. © 2015 Scientific Reports.

Topics

• nanocomposite
• impedance spectroscopy
• iron
• magnetization