Magnetic properties of oblique deposited (FeCoNiNbB)x(SiO2)1-x granular films in a wide x range

Abstract

(Fe57Co24Ni4Nb2B13)x-(SiO2)1−x nano-granular thin films in a wide x range were fabricated by magnetron sputtering by oblique incidence. Excellent soft magnetic properties have been achieved with variable in-plane uniaxial magnetic anisotropy field Hk. For same oblique angle θ, with decreasing x, Hk increases first and reaches maximum at x=0.88, then decreases; while the coercivity in the easy axis changes slightly and is less than 10 Oe and the resitivity ρ increases monotonously and exhibits a higher rate in x<0.88. For films with θ=15°, the sample x=0.88 possesses a high FMR frequency fr of 5.4 GHz and a large permeability μ′ of 40 up to 4.1 GHz. The sample x=0.66 has both high resistivity and excellent soft magnetic properties, of which the coercivities in hard and easy axes are 3.1 and 2.4 Oe, respectively, Hk is 60 Oe, and ρ reaches 3.1×103 μΩ cm. The magnetic spectrum μ=μ′−jμ″ shows that μ′ is more than 150 below 0.70 GHz and fr reaches 1.70 GHz.