MECHANOSYNTHESIS, CRYSTAL STRUCTURE, MAGNETIC AND ABSORPTION PROPERTIES OF Al SUBSTITUTED BaFe12O19

Abstract

The Aluminums (Al) substituted on M-type barium ferrite (BaFe12O19) is one of the magnetic materials, which can be applied to the microwave band working at high frequencies. The purpose of this paper is to investigate the effect of Al substitution for Fe3+ ions on the structure, magnetic and absorption behavior of M-type barium ferrite. The sample was prepared by mechano-synthesis using high-energy milling (HEM). In this research, Fe ion in BaFe12O19 was substituted by Al ion to form BaFe12-xAlxO19 for x = 0.0,BaFe10Al2O19 for x = 2.0 and BaFe8Al4O19 for x = 4.0 which is called as BAl-0, BAl-2 and BAl-4 sample, respectively. The stainless steel balls were used for the milling with a ball-to-powder sample ratio of 5. The mixing and milling for each the sample was conducted for 5 hours in ethanol medium and dried at 100oC in oven for 24 hours and then followed by heat treatment at 1100°C during 1h in the atmosphere media. The sample was characterized using X-rays diffractometer (XRD), Scanning Electron Microscope (SEM), Vibrating Sample Magnetometer (VSM) and Vector Network Analyzer (VNA). The result indicates that the addition of Al ion lead to the change cell parameters, volume, and the particles size. The magnetic behavior such as magnetic coercivity (Hc), magnetization saturation (Ms) and remanent (Mr) changed significantly with the substitution of Al ions. The optimum reflection loss (RL) is found to be –35dB at 14GHz for BaFe10Al2O19 (BAl-2) sample. It is shown that Al substitutions change the particle size, ferromagnetic resonant frequency, and structural and magnetic behavior of M-type barium ferrite.

The Impact of Al3+ ion substitution on microwave absorption of hexaferrite compound Ba0.6Sr0.4Fe12−xAlxO19 (x = 0.25, 0.50, 0.75, and 1.00)

“…The same thing happened to the samples BaFe (11.5-x) Ti 0.5 Al x O 19 [11] and SrAl x Fe 12-x O 19 [12], whereas the sample Sr 0.5 Ca 0.2 Nd 0.3 Fe 12-x (Al 0.5 Co 0.5 ) x O 19 will increase for x = 0.0-0.2, decrease for x = 0.2-0.3, and increase again for x > 0.3 [13]. On the other hand, Al 3+ ion substitution can increase the value of reflection loss (RL) up to −35.0 dB, but with a narrow bandwidth of only about 1.25 GHz [2]. Recent research conducted by Chou shows that aluminum-substituted M-type Strontium hexaferrite (SrM-Al, SrFe 12−x Al x O 19 , 0 x 4) has a uniform microstructure and excellent magnetic properties where the coercive field increases with Al 3+ doping despite the magnetization significantly reduced [14].…”

“…In addition, the structure's potential energy is low, making it stable. This substance can be used as a harvesting magnet [1] and a microwave absorber (anti-radar) [2,3]. A material must have a high reflection loss (RL) and a broad frequency range in order to be used as a microwave absorber.…”

“…Samples were prepared using numerous techniques, including the glycin-nitrate method [12], the standard ceramic method [13,16], and solid-state reaction with milling [1][2][3]17]. Based on these different methods, the solid-state reaction is a simple method that can be used on a large scale and is inexpensive but requires treatments at temperatures as high as 1,000 °C.…”