High-Quality Ferromagnet Fe 3 GeTe 2 for High-Efficiency Electromagnetic Wave Absorption and Shielding with Wideband Radar Cross Section Reduction.

A high-quality Fe 3 GeTe 2 single crystal with good electrical, magnetic, and electromagnetic wave absorption and shielding properties was prepared in a large quantity (10 g level) by solid-phase sintering and recrystallization method, which would promote its in-depth research and practical application. It has good room-temperature electrical properties with a mobility of 42 cm 2 /V·s, a sheet (bulk) carrier concentration of +1.64 × 10 18 /cm 2 (+3.28 × 10 20 /cm 3 ), and a conductivity of 2196.35 S/cm. Also, a Curie temperature of 238 K indicates the high magnetic transition temperature and a paramagnetic Curie temperature of 301 K shows the large ferromagnetic-paramagnetic transition zone induced by the residual short-range ferromagnetic domains. Particularly, Fe 3 GeTe 2 is in a loosely packed state when used as a loss agent; the electromagnetic wave absorption with a reflection loss of -34.7 dB at 3.66 GHz under thin thickness was shown. Meanwhile, the absorption band can be effectively regulated by varying the thickness. Moreover, Fe 3 GeTe 2 in a close-packed state exhibits terahertz shielding values of 75.1 and 103.2 dB at very thin thicknesses of 70 and 380 μm, and the average shielding value is higher than 47 dB, covering the entire bandwidth from 0.1 to 3.0 THz. Furthermore, by using Fe 3 GeTe 2 as a patch, the wideband radar cross-section can be effectively reduced by up to 33 dBsm. Resultantly, Fe 3 GeTe 2 will be a promising candidate in the electromagnetic protection field.