Arackal, S and Nozawa, K and Kahmei, R and Loi, TT and Yabukami, S and Shivashankar, SA and Yamaguchi, M and Bhat, N and Sai, R (2022) Resonance frequency above 20 GHz in superparamagnetic NiZn-ferrite. In: Applied Physics Letters, 121 (6).
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Abstract
We investigate the frequency dispersion of complex permeability in the GHz range in superparamagnetic nickel-zinc ferrite thin films with different Ni/Zn ratios using a microstrip probe. The films, comprising crystallites as small as 3 nm and deposited by a microwave-irradiation-Assisted solvothermal method, exhibit the coexistence of two resonance characteristics-A ferromagnetic resonance peak (f r) at ∼2 GHz and a superparamagnetic resonance peak (f b) above 20 GHz, breaching Snoek's limit. The high value of f r is attributed to the high surface anisotropy and far-from-equilibrium distribution of cations in the lattice, while f b is attributed to the thermally driven superparamagnetic relaxation of ferrite nanocrystallites in the thin films. This work demonstrates the feasibility of employing superparamagnetic ferrite thin films so deposited as excellent CMOS-integrable magnetic components for high-speed and high-frequency electromagnetic device applications.
| Item Type: | Journal Article |
|---|---|
| Publication: | Applied Physics Letters |
| Publisher: | American Institute of Physics Inc. |
| Additional Information: | The copyright for this article belongs to the Authors. |
| Keywords: | Electromagnets; Microwave irradiation; Superparamagnetism; Thin films, Complex permeability; Ferrites thin films; Frequency dispersion; Micro-strips; Microwave- irradiations; Ni-Zn ferrites; Nickel Zinc ferrites; Resonance frequencies; Resonance peak; Superparamagnetics, Ferrite |
| Department/Centre: | Division of Interdisciplinary Sciences > Centre for Nano Science and Engineering |
| Date Deposited: | 14 Sep 2022 09:02 |
| Last Modified: | 14 Sep 2022 09:02 |
| URI: | https://eprints.iisc.ac.in/id/eprint/76442 |
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