Broadband ferromagnetic resonance in Mn-doped Li ferrite nanoparticles. (April 2019)

• Record Type: Journal Article
• Authors: Hernández-Gómez, P.; Muñoz, J.M.; Valente, M.A.; Graça, M.P.F.
• Is Part Of: Materials research bulletin. Volume 112(2019)
• Page Start: 432
• Page End: 437
• Publication Date: 2019-04
• Subjects: A. Magnetic materials -- A. Oxides -- B. Sol-gel chemistry -- B. Magnetic properties; Materials -- Periodicals; Crystal growth -- Periodicals; Matériaux -- Périodiques; Cristaux -- Croissance -- Périodiques; Crystal growth; Materials; Periodicals; 620.11
• DOI: 10.1016/j.materresbull.2018.09.005
• Languages: English
• ISSNs: 0025-5408

Abstract

Graphical abstract: Highlights: Sol-gel fabrication of Mn doped Li ferrite nanoparticles. Magnetoabsorption measurement in nanoparticles with broadband FMR system. Materials candidates for absorbers in 1–8 GHz frequency range. Abstract: Lithium ferrites are well known materials due to their numerous technological applications especially in microwave devices. Mn-doped lithium ferrite nanoparticles were prepared by sol-gel technique by means of Pechini method, and then annealed at different temperatures in 250–1000 °C range. XRD confirms spinel formation with particle size in the 15–200 nm range, with increased size with annealing temperature. Microwave magnetoabsorption data of annealed lithium ferrite nanoparticles, obtained with a broadband system based on a network analyzer operating up to 8.5 GHz are presented. At fields up to 200 m T we can observe a broad absorption peak that shifts to higher frequencies with magnetic field according to ferromagnetic resonance theory. The amplitude of absorption, up to 85%, together with the frequency width of about 4.5 GHz makes this material suitable as wave absorber. Samples annealed at higher temperatures show a behaviour similar to polycrystalline samples, thus suggesting their multidomain character.