Frequency-dependent complex permeability in Zr-substituted permalloy thin films

Abstract

In this work, we investigate Zr substitution in Permalloy Ni 80 Fe 20 thin films in order to control the magnetic properties and then to tune the resonance frequency at lower values with high permeability levels. The structural transition from a crystalline to an amorphous phase, saturation induction, in-plane anisotropy, electrical resistivity, and frequency-dependent permeability are studied for the Zr content ranging from 0 to 17% at. The high-frequency permeability of these (Ni 80 Fe 20 ) 1 Zr films is first measured in the 0.1-3-GHz range using a permeameter. Assuming a gyroresonance mechanism, the frequency-dependence of the permeability is studied as a function of the magnetization, anisotropy field, and damping parameter deduced from ferromagnetic resonance characterizations. For a Zr concentration of 17%, a resistivity of 260 cm is obtained as well as very soft properties ( 0 5 Oe). We also show that the permeability is drastically affected by the Zr substitution with a significant shift of the resonance frequency from 600 to 300 MHz, which correlates with the decrease of the saturation induction and a very low anisotropy.

Ultrahigh frequency magnetic susceptibility of Co and Fe cylindrical films deposited by pulsed laser ablation

“…Consequently, we have fitted the experimental values of the real and imaginary parts of the circular magnetic susceptibility of the Co cylindrical films at frequencies up to 6 GHz to the the LLG equation solutions for planar films with an easy magnetization axis perpendicular to the direction of the uhf magnetic field. 24 In this computation, the fitting parameters were the damping coefficient ␣ and the FMR frequency r . The value of the saturation magnetization ͑ 0 M s ͒ of the Co films was 1.4 T. Thus, Fig.…”

“…We have fitted the former values to theoretical ones obtained from the solutions of the LLG equation for films. 24 The only fitting parameter in this case was the value of the anisotropy field H k . The value of H k of the best fit was 90 Oe, which was similar to the experimental value found from VSM measurements as displayed in Fig.…”

Influence of the electrical resistivity of a ferromagnetic thin film on its permeability measurement performed with a permeameter

“…We choose Gilbert model [15] that involves static parameters deduced from FMR measurements. For a saturated film with an in-plane uniaxial anisotropy H k along the easy axis, the frequencydependent permeability is given [16] mðf Þ ¼…”