Magnetic properties of [FeCoSiN/SiNx]18 multilayer thin films for applications in GHz range

• Published in: Journal of alloys and compounds 2016-09, Vol.680, p.531-537
• Main Authors: Liu, X.L., Wang, L.S., Luo, Q., Xie, Q.S., Zhang, Q.F., Liu, X., Bai, F.M., Peng, D.L.
• Format: Article
• Language: English
• Subjects: High-frequency magnetic properties; Insulating layer thickness; Multilayer films; Surface roughness
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2016.03.308

[FeCoSiN/SiNx]18 multilayer thin films with different SiNx layer thickness (t) ranging from 0.75 to 4 nm were fabricated by reactive magnetron co-sputtering without applying an external induced magnetic field. The grain size, morphology, electrical properties, and static and dynamic magnetic properties of [FeCoSiN/SiNx]18 multilayer thin films were investigated systematically. The results indicated that SiNx layer thickness had a profound impact on the physical properties of the multilayer thin films. The in-plane uniaxial magnetic anisotropy field (from 114 ± 21 to 163 ± 14 Oe), ferromagnetic resonance frequency (from 4.09 to 4.64 GHz) and resistivity (from 188 to 333 μΩ cm) could be tailored effectively by adjusting the SiNx layer thickness from 0.75 to 4 nm. Moreover, when the SiNx layer thickness reached 2 nm, the continuous growth of FeCoSiN polycrystalline layers was to be interrupted completely and it would result in a minimum grain size of 4.9 ± 0.7 nm. The root mean square roughness of multilayer thin films also acquired a minimum value of 0.8 nm and the corresponding easy axis coercivity achieved a minimum value of 2.8 ± 0.1 Oe. •The [FeCoSiN/SiNx]n multilayer thin films were prepared by alternant magnetron sputtering.•The influence of SiNx insulating layer thickness on high-frequency properties was studied.•The multilayer thin films exhibited excellent high-frequency properties.