Highly efficient inorganic-coated FeSiAl/biotite soft magnetic composites

FeSiAl/biotite soft magnetic composites were synthesized by mixing atomized FeSiAl and biotite at a specific mass ratio via ball milling. The structures, morphologies, elemental distributions, and magnetic properties of the FeSiAl/biotite composites were systematically studied. Scanning electron microscopy showed that the layered biotite was stripped into nanoflakes via high-speed ball milling and evenly distributed on the surface of FeSiAl, forming an efficient inorganic insulating coating layer. In magnetic performance tests, the FeSiAl/1-wt.%-biotite composite showed not only a high effective permeability but also low eddy current loss. Complex permeability measurements showed that the addition of biotite could reduce the eddy current loss and improve the relaxation frequency of FeSiAl/biotite composites, rendering them suitable for high-frequency applications. The FeSiAl/1-wt.%-biotite mixture exhibited good magnetic properties, with an effective permeability of 106.0, and magnetic loss of 219.0 kWm−3 at f = 50 kHz and Bm = 0.1 

Observation of the Spin-Glass Behavior in Co-Based Antiperovskite Nitride GeNCo₃

Single-phase antiperovskite nitride GeNCo₃ with space group <i>Pm</i>3̅<i>m</i> is successfully synthesized by a solid–gas reaction. The crystal structure, magnetism, specific heat at low temperatures, Hall effect, and electrical and thermal transport properties are widely investigated. Exhilaratingly, a canonical spin-glass (SG) behavior is observed in GeNCo₃ with a freezing temperature <i>T</i>₀ = 79.43 K, dynamical exponent <i>zν</i> = 6.156, and flipping time τ₀ = 5.0 × 10^–12 s. The origin of the SG state in GeNCo₃ is likely due to the atomic disorder introduced by the Ge vacancies. This is further proven by the measurements of Ge_0.9NCo₃ with more Ge deficiencies