Microstructure and room temperature ferromagnetism of double-layered MnxGe1−xTe polycrystalline modified by the space-layer thickness

Dilute magnetic semiconductor (DMS) nanomaterials have broad application prospects in spin electronics, but low Curie temperatures (TC) hinders their applications. In this work, MnxGe1−xTe (MGT) polycrystalline with a double-layer structure were fabricated on Si (100) substrates using ion beam sputtering. When compared to single-layer sample, the double-layer polycrystalline formed uneven stress distribution on the surface and preferred nucleation site, thus promoting the growth of the MGT polycrystalline. The saturation magnetization (MS) and remanent magnetization (MR) of double-layered polycrystalline were measured to be 4.43 × 10−5 emu/mm2 and 1.05 × 10−5 emu/mm2, respectively, and the TC reached 373.5 K. When comparing it to the single-layer sample, on the one hand, the double-layer sample shows enhanced magnetic properties and strain due to the increased Ge content. On the other hand, the quantum confinement effect and the relative strength of the Ge-Ge bond will affect the magnetic properties of the double-layer sample. In summary, the work not only provides a feasible way to improve the magnetic performance of DMS, but also improves the temperature application range of high-performance devices where polycrystalline are compatible with traditional complementary oxide metal (CMOS) technology.