Exchange hardening in FePt/Fe3Pt dual exchange spring magnet: Monte Carlo modeling

The FePt/Fe3Pt bilayer, a model dual exchange spring system with intergranular exchange hardening between A1 and L1(0) FePt and interfacial exchange hardening between L1(0) FePt and Fe3Pt is investigated systematically for varying thickness of soft layer (Fe3Pt). Optimal exchange hardening with an appreciable coercivity (H-c) is observed for the bilayer system with a thickness of 2 nm of the soft layer. Recoil studies reveal coherent magnetization up to a reverse field of 7 kOe in this sample, with possible application for memory device. Monte Carlo simulation is performed to analyze the effect of magnetic anisotropy and interactions on the reversal mechanism at the interface of the bilayer system. The angular remanence of bilayered system reveals that the easy axis of L1(0) FePt and Fe3Pt are mutually perpendicular. (C) 2016 Elsevier B. V. All rights reserved.