Title :
Fabrication and study of Ni75Fe25-SiO2 granular films for high frequency application
Author :
Ge, Shihui ; Yang, Xiaolin ; Kim, Kwang Youn ; Xi, Li ; Kou, Xiaoming ; Yao, Dong-Sheng ; Li, Binsheng ; Wang, Xinwei
Author_Institution :
Key Lab. for Magnetism & Magnetic Mater., Lanzhou Univ., China
Abstract :
A series of (Ni75Fe25)x(SiO2)(1-x) films with different volume fraction x is fabricated by magnetron co-sputtering technique. The structure, magnetic and high frequency properties are investigated systematically by X-ray diffraction, transmission electronic microscopy, vibrating sample magnetometer, resistivity and complex permeability measurements. The results show that the films consist of Ni75Fe25 magnetic metal particles uniformly embedded in the insulating SiO2 matrix. The (Ni75Fe25)x(SiO2)(1-x) films exhibit excellent soft magnetic properties in a wide x range from 0.81 to 0.52 with coercivity Hc not exceeding 5 Oe, which is ascribed to the exchange coupling between magnetic particles due to the long exchange length of Ni75Fe25 alloy. The smallest Hc is 1.1 Oe obtained for the sample of x=0.81 with high electrical resistivity ρ=167 μΩ·cm, and the real part μ´ of its initial complex permeability keeps constant of 170 below 550MHz while the imaginary part μ´´ is less than 26. The rapid increase of μ´´ at the frequency higher than 600MHz can be attributed to the ferromagnetic resonance, whose frequency is estimated to be about 2.2GHz. For the film of x= 0.52, besides the low Hc (∼3Oe), very high ρ over 1.18×104 μΩ·cm has been obtained, implying that this film is quite promising for very high frequency application.
Keywords :
X-ray diffraction; discontinuous metallic thin films; electric resistance measurement; iron alloys; magnetic particles; magnetic permeability measurement; magnetic thin films; magnetometers; nickel alloys; silicon compounds; soft magnetic materials; sputtered coatings; transmission electron microscopy; Ni75Fe25-SiO2; complex permeability measurements; ferromagnetic resonance; granular films fabrication; high frequency application; high frequency property; magnetic property; magnetic thin films; magnetron co-sputtering; resistivity measurements; structural property; transmission electronic microscopy; vibrating sample magnetometer; x-ray diffraction; Fabrication; Frequency estimation; Iron; Magnetic films; Magnetic force microscopy; Magnetic properties; Magnetometers; Soft magnetic materials; Transmission electron microscopy; X-ray diffraction; Frequency response; magnetic thin films; soft magnetic materials;
Journal_Title :
Magnetics, IEEE Transactions on
DOI :
10.1109/TMAG.2005.854904