Coercivity enhancement by Ru pinning layer in FePt thin films

Abstract

The face-centered-tetragonal-(001) FePt thin films were prepared by dc magnetron sputtering Fe50Pt50 layer onto Cr91Ru9 underlayer at 400 °C. In order to enhance the coercivity and to obtain a relative lower exchange coupling medium with nucleation reversal mechanism, a nonmagnetic Ru pinning layer inserted in the magnetic layer is described to introduce controllable defects to impede domain-wall motion. A 60% increasing of the out-of-plane coercivity was observed after 1 nm Ru nonmagnetic pinning layer added between the FePt magnetic layers. From angular dependence of the coercivity measurement, the magnetization reversal mechanism was observed to shift from the typical domain-wall motion behavior to the nucleation mode by increasing the thickness of the pinning layer.

Embedding S = 1/2 Kagome-like Lattice in Reduced Graphene Oxide

“…Further, the crystallites are chemically bonded to rGO sheets (discussed above), which could potentially elevate the interparticle interaction (kind of dipolar) compared to that in pristine clinoatacamite. 30 The chemical bonding between the clinoatacamite and rGO can also induce spin arrangement anisotropy at the interface and/ or lead to domain wall pinning; 34,35 thus, significant enhancement in the coercivity value of our clinoatacamite−rGO nanocomposite system (Figure S10c) is ascribed to the combined effect of surface anisotropy and interparticle interactions. 30 A reduction in the remanent magnetization at 5 K in the clinoatacamite−rGO nanocomposite when compared to that of pristine clinoatacamite is also indicative of surface effects.…”

Do magnetically modified PtFe/C catalysts perform better in methanol electrooxidation?

“…Watanabe and co-workers extended the application of PtFe (obtained by Ar-sputtering of the parent metals) in PEMFC to hydrogen oxidation and found that the PtFe alloys also exhibited excellent CO tolerance [10][11][12]. Li et al also tested some of their PtFe DMFC cathode catalysts for MOR [8], and observed an earlier onset of methanol oxidation ( sputtering-prepared PtFe alloy has been known to be ferromagnetic [13]. FePt nanoparticles containing near-equal atomic percentage of Fe and Pt are an important class of magnetic nanomaterials and their applications have been recently reviewed by Sun [14].…”

The effects of pinning layer on the magnetic properties of FePt perpendicular media

“…The defects in bulk materials by elements doping were reported to form pinning sites in magnetic materials to pin the domain wall motion and thus enhance the coercivity of the magnetic materials [1]. The inhomogeneities in the interfaces of the additional nonmagnetic ruthenium (Ru) layer and FePt layers were found to introduce pinning effects to the media [2,3]. However, the coercivity enhancement by the pinning effects was not as significant as expected after Ru pinning layer inserted.…”