Significant high-frequency electromagnetic wave absorption performance of Ni2+xMn1−xGa alloys

The electromagnetic wave (EMW) absorption properties in Heusler-type ferromagnetic Ni 2+ x Mn 1− x Ga alloys were systematically investigated. Significant electromagnetic absorption performance at 2.0–18.0 GHz was observed for Ni 2+ x Mn 1− x Ga alloys. The values of the complex permittivity ( ε r ) and permeability ( μ r ), as well as the reflection loss (RL), peak frequency ( f m ) and bandwidth (Δ f ) of Ni 2+ x Mn 1− x Ga can be effectively tuned by the alloy component (Ni/Mn ratio). The magnetic loss factor (tan δ μ ) shows pronounced multi-resonance behavior, and dielectric loss factor (tan δ ε ) has dramatic dielectric relaxation. The RL exceeding − 10 dB corresponding to 90% absorption of incident microwave can be achieved for the Ni 2 MnGa in a broad frequency range of 6.3–18.0 GHz together with the thickness from 1.66 to 4.75 mm. Particularly, the maximum RL reaches − 49.1 dB at 13.3 GHz with the thickness of 2.57 mm for Ni 2 MnGa. The present results indicated that the ferromagnetic Ni 2+ x Mn 1− x Ga alloys could be attractive candidates for broadband and high-frequency EMW absorption.