Broadband Magnetic Response of Periodic Arrays of FeNi Dots

• Published in: IEEE transactions on magnetics Vol. 44; no. 11; pp. 3063 - 3066
• Main Authors: Sierra, J.F., Awad, A.A., Kakazei, G.N., Palomares, F.J., Aliev, F.G.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: New York, NY IEEE 01-11-2008; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Arrays; Broadband; Cross-disciplinary physics: materials science; rheology; Demagnetization; Demagnetizing; Dynamic response; Dynamic tests; Exact sciences and technology; Frequency; High definition video; Magnetic analysis; Magnetic confinement; Magnetic cores; Magnetic devices; Magnetic resonance; Magnetism; Magnetometers; Materials science; Mathematical analysis; nanotechnology; Nucleation; Other topics in materials science; Physics; Saturation magnetization; Spin waves; Temperature; nanotechnology; Magnetic devices; Magnetic resonance; Magnetic properties
• ISSN: 0018-9464; 1941-0069
• DOI: 10.1109/TMAG.2008.2002527

We present a study of magnetization dynamics at room temperature in periodic arrays of 50 nm thick FeNi (Py) circular magnetic dots of 500 nm radius and different center to center distance (1200 and 2500 nm), by using a broadband magnetometer based on vector network analyzer which works between 300 kHz and 8.5 GHz. We also present a comparison between the dynamic response, ferromagnetic resonance (FMR) and its linewidth, with static magnetic characteristics such as magnetization curves. The FMR peak appears just above the nucleation field and is perfectly described by Kittel formula taking into account the demagnetizing factor of an individual magnetic dot. In addition to FMR we observed a spin wave resonance below the uniform mode, which could be attributed to spin waves in confined systems. The FMR linewidth shows a significant broadening close to the field region corresponding to nucleation of magnetic vortex.