Anomalous Hall effect in NiPt thin films

Abstract

We study Hall effect in sputtered NixPt1-x thin films with different Ni concentrations. Temperature, magnetic field and angular dependencies are analyzed and the phase diagram of NiPt thin films is obtained. It is found that films with sub-critical Ni concentration exhibit cluster-glass behavior at low temperatures with a perpendicular magnetic anisotropy below the freezing temperature. Films with over-critical Ni concentration are ferromagnetic with parallel anisotropy. At the critical concentration the state of the film is strongly frustrated. Such films demonstrate canted magnetization with the easy axis rotating as a function of temperature. The magnetism appears via consecutive paramagnetic - cluster glass - ferromagnetic transitions, rather than a single second-order phase transition. But most remarkably, the extraordinary Hall effect changes sign at the critical concentration. We suggest that this is associated with a reconstruction of the electronic structure of the alloy at the normal metal - ferromagnet quantum phase transition.Comment: 12 pages, 17 figure

Nearly isotropic spin-pumping related Gilbert damping in Pt/Ni81Fe19/Pt

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In situ transport characterization of magnetic states in Nb/Co superconductor/ferromagnet heterostructures

“…Figure 1i shows corresponding Hall resistances measured as shown in the sketch from Figure 1a . The measured Hall signal contains a small (<0.1%) admixture of the longitudinal resistance, which has been subtracted as described in [ 59 ]. It is seen that a noticeable Hall signal appears only within the resistive transition region and is non-linear (bias-dependent) even at low bias.…”

First‐principles investigation of the structure, mechanical and hydrogen adsorption behavior of NiPt nanoparticle

“…[17][18][19][20][21] Therefore, the NiPt nanoparticle is a fascinating magnetic storage material owing to the excellent magnetic behavior. 22,23 For example, the curie temperature and magnetic moments of NiPt nanoparticles are sensitive to the concentration of Ni. 24 The measured magnetic moments of NiPt increase from approximately 0.9 μ B /atom under 15 K to 1.9 μ B /atom under 300 K. 25 In addition, the NiPt nanoparticle is a promising catalyst due to the physical and chemical properties.…”

“…Compared to the pure Pt, numerous works have shown that the NiPt nanoparticles exhibit excellent cyclic voltammetry properties and good electrochemically active surface area, which can enhance the catalytic activity of pure platinum (Pt) and reduce the cost of Pt catalyst 17‐21 . Therefore, the NiPt nanoparticle is a fascinating magnetic storage material owing to the excellent magnetic behavior 22,23 …”