Analyzing the Microwave Absorption Properties of BaFe 12 O 19 , Ba 4 MnZnFe 36 O 60 and NiFe 2 O 4 Particles
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https://doi.org/10.1007/s11664-020-08317-1 Ó 2020 The Minerals, Metals & Materials Society
Analyzing the Microwave Absorption Properties of BaFe12O19, Ba4MnZnFe36O60 and NiFe2O4 Particles MINA MORADNIA,1,4 MEHDAD FATHI,2,5 MOSTAFA MEHDIPOUR and HOOMAN SHOKROLLAHI3,7
,2,6
1.—Magnetic Materials Research Lab, Department of Materials Engineering, University of Houston, Houston, TX, USA. 2.—Magnetic Materials Research Lab, Department of Materials Engineering, Faculty of Mechanical Engineering, University of Tabriz, Tabriz, Iran. 3.—Electroceramics Group, Department of Materials Science and Engineering, Shiraz University of Technology, Shiraz, Iran. 4.—e-mail: [email protected]. 5.—e-mail: [email protected]. 6.—e-mail: [email protected]. 7.—e-mail: [email protected]
A stoichiometric ratio of the Merck chlorides of Barium, Iron, nickel and NaOH as an agent was used to obtain the nano-crystalline ferrites (BaFe12O19, Ba4MnZnFe36O60 and NiFe2O4) by a combination of co-precipitation and highenergy reactive milling (RM) methods. After milling, the as-synthesized ferrite materials were exposed to a heat treatment at 1100°C for 4 h with the heating rates of 10°/min. After cooling the powders of ferrites inside the furnace, they were sintered at 1200°C for 4 h. The microstructural, structural, magnetic, and microwave absorption features were examined by x-ray diffractometry (XRD), scanning electron spectroscopy (SEM), vibrating-sample magnetometry (VSM) and network analysis (VNA), respectively. As can be seen in the hysteresis loops, both saturation magnetization and coercivity were changed by altering the ferrite kind. After sintering, the Ba-ferrites showed a smaller amount of saturation magnetization of 300 G (0.03 T) and a larger quantity of intrinsic coercivity 1.8 kOe (144 KA/m) compared to the Ni-ferrite and Ba4MnZnFe36O60. After sintering, the samples’ reflection loss spectra were changed and reached the maximum value of 35 dB (at resonance frequency) for NiFe2O4, making it suitable for application in the microwave and resonance absorbers. Key words: Ferromagnetic particles, co-precipitation, sintering, magnetic and microwave absorption properties
INTRODUCTION A particular kind of environment-related pollution is increasing: the broad application of electromagnetic (EM) waves in wireless communications like EM waves of 0.8–1.2 GHz, which are employed for cell phones, 2.45 GHz for the purpose of electronic ranges, 5.6–8.2 GHz (G-band) for synthetic aperture radar (SAR) 1,2 or microwave communications on the ground, 8.2–12.4 GHz (X-band) and
(Received February 5, 2020; accepted July 4, 2020)
12.4–18 (Ku-band) for SAR or electron spin resonance (ESR) equipment. These have caused numerous investigations within the domain of ‘microwave absorbing materials’ so as to minimize the detrimental impacts of electromagnetic waves upon biological tissues in the shape of electromagnetic interference (EMI), accompanied by their alleged application as radar absorbing material (RAM).3 Nowadays, ferrit
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