Tunable Twin Matching Frequency (fm1/fm2) Behavior of Ni1−xZnxFe2O4/NBR Composites over 2–12.4 GHz: A Strategic Material System for Stealth Applications

• Published in: Scientific reports Vol. 7; no. 1; p. 44457
• Main Authors: Saini, Lokesh, Patra, Manoj Kumar, Jani, Raj Kumar, Gupta, Goutam Kumar, Dixit, Ambesh, Vadera, Sampat Raj
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group 15.03.2017
• Subjects: Aluminum; Powder; Rubber; Strategic materials
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/srep44457

Abstract The gel to carbonate precipitate route has been used for the synthesis of Ni 1−x Zn x Fe 2 O 4 (x = 0, 0.25, 0.5 and 0.75) bulk inverse spinel ferrite powder samples. The optimal zinc (50%) substitution has shown the maximum saturation magnetic moment and resulted into the maximum magnetic loss tangent (tanδ m ) > −1.2 over the entire 2–10 GHz frequency range with an optimum value ~−1.75 at 6 GHz. Ni 0.5 Zn 0.5 Fe 2 O 4 - Acrylo-Nitrile Butadiene Rubber (NBR) composite samples are prepared at different weight percentage (wt%) of ferrite loading fractions in rubber for microwave absorption evaluation. The 80 wt% loaded Ni 0.5 Zn 0.5 Fe 2 O 4 /NBR composite (FMAR80) sample has shown two reflection loss (RL) peaks at 5 and 10 GHz. Interestingly, a single peak at 10 GHz for 3.25 mm thickness, can be scaled down to 5 GHz by increasing the thickness up to 4.6 mm. The onset of such twin matching frequencies in FMAR80 composite sample is attributed to the spin resonance relaxation at ~5 GHz ( f m1 ) and destructive interference at λ m /4 matched thickness near ~10 GHz ( f m2 ) in these composite systems. These studies suggest the potential of tuning the twin frequencies in Ni 0.5 Zn 0.5 Fe 2 O 4 /NBR composite samples for possible microwave absorption applications.