Exploring Broadband Electromagnetic Absorption Characteristics and Composition Optimization in Novel Synthesized Ni₂Fe_1+xGe_1−x Alloy Powders

This study reports for the first time the successful synthesis of a novel series of Ni₂Fe_1+xGe_1−x (x = 0.25, 0.50, 0.75, 0.90) polycrystalline alloy materials with L2₁ austenite structure using the mechanical alloying method. Notably, the Ni₂Fe_1+xGe_1−x alloys demonstrate excellent electromagnetic wave absorption performance across the entire 2–18 GHz frequency range, and by adjusting the composition ratio of iron and germanium, it is possible to effectively regulate their complex permittivity () and permeability (), thereby adjusting the reflection loss. All Ni₂Fe_1+xGe_1−x samples show an effective electromagnetic wave absorption effect of more than −10 dB, indicating that 90% of the electromagnetic waves are efficiently absorbed. Among them, the Ni₂Fe_1.5Ge_0.5 sample achieves an outstanding −43.5 dB reflection loss at 3.2 GHz, and the maximum effective absorption bandwidth reaches 5.8 GHz (11.8–17.6 GHz) with just a 1.6 mm thickness, fully covering the Ku band. This excellent absorption ability comes from the strong ability of the material to reduce signal strength and its perfect impedance matching. This study first shows the high potential of Ni₂Fe_1+xGe_1−x ferromagnetic alloys as effective, wide‐range electromagnetic wave absorbers. It suggests the ferromagnetic Ni₂Fe_1+xGe_1−x alloys hold promise as appealing candidates for broadband and high‐efficiency electromagnetic wave absorption.