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Electric and Magnetic Properties of Bi0.80Ba0.20FeO3-Doped Ba0.85Ca0.15Ti0.90Zr0.10O3 Ceramics Prepared via the Solid-State Combustion Technique
(2023-05-01)
Thawong, Pichittra
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Prasertpalichat, Sasipohn
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Suriwong, Tawat
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Pinitsoontorn, Supree
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Vittayakorn, Naratip
Lead-free (1−x)Ba<inf>0.85</inf>Ca<inf>0.15</inf>Ti<inf>0.90</inf>Zr<inf>0.10</inf>O<inf>3</inf>–xBi<inf>0.80</inf>Ba<inf>0.20</inf>FeO<inf>3</inf> [(1−x)BCTZ–xBBF] ceramics, with BBF content (x) between 0 and 0.4, are prepared via the solid-state combustion technique. The effect of BBF content on the phase formation, microstructure, and electric and magnetic properties of BCTZ is studied. From the Rietveld refinement analysis, the BCTZ ceramic shows coexisting orthorhombic and tetragonal phases, with a ratio of 35.4:64.6 and the percentage of the tetragonal phase continuously increases when x increases from 0.02 to 0.1, and becomes purely tetragonal at x ≥ 0.2. When x increases, the average grain size, density, and relative density continuously decrease while the unit cell volume enlarges. The dielectric constant at room temperature (ε<inf>R</inf>) tends to decrease while the dielectric loss at room temperature (tan δ<inf>R</inf>) increases with increased BBF content. For x = 0, a pure BCTZ ceramic, a well-saturated P–E loop is observed with a polarization (P<inf>r</inf>) and coercive field (E<inf>c</inf>) of 8.94 μC cm−2 and 4.06 kV cm−1, respectively. The ferroelectricity drastically decreases with x = 0.02. For x ≥ 0.06, the leakage current increases, which suppresses the ferroelectricity. With no BBF content (x = 0), the ceramic has diamagnetic properties that change to paramagnetic properties with x = 0.02–0.06 and finally to ferromagnetic properties when the BBF increases between 0.10 and 0.40. For x = 0.10–0.40, the remnant magnetization (M<inf>r</inf>) continuously increases.
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Effect of Co2+ substitution in B-sites of the perovskite system on the phase formation, microstructure, electrical and magnetic properties of Bi0.5(Na0.68K0.22Li0.10)0.5TiO3 ceramics
(2022-09-01)
Bhupaijit, Pamornnarumol
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Kaewsai, Chonnarong
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Suriwong, Tawat
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Pinitsoontorn, Supree
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Yotthuan, Surirat
Bi<inf>0.5</inf>(Na<inf>0.68</inf>K<inf>0.22</inf>Li<inf>0.10</inf>)<inf>0.5</inf>Ti<inf>1−x</inf>Co<inf>x</inf>O<inf>3</inf> lead-free perovskite ceramics (BNKLT−xCo, x = 0, 0.005, 0.010, 0.015 and 0.020) were fabricated via the solid-state combustion technique. A small-amount of Co2+ ion substitution into Ti-sites led to modification of the phase formation, microstructure, electrical and magnetic properties of BNKLT ceramics. Coexisting rhombohedral and tetragonal phases were observed in all samples using the X-ray diffraction (XRD) technique. The Rietveld refinement revealed that the rhombohedral phase increased from 39% to 88% when x increased from 0 to 0.020. The average grain size increased when x increased. With increasing x, more oxygen vacancies were generated, leading to asymmetry in the bipolar strain (S−E) hysteresis loops. For the composition of x = 0.010, a high dielectric constant (ε<inf>m</inf>) of 5384 and a large strain (S<inf>max</inf>) of 0.23% with the normalized strain (d*<inf>33</inf>) of 460 pm·V−1 were achieved. The BNKLT−0Co ceramic showed diamagnetic behavior but all of the BNKLT−xCo ceramics exhibited paramagnetic behavior, measured at 50 K.
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Effect of BFCO Doping on Phase Structure, Microstructure, Electric and Magnetic Properties of BNKLT Ceramics Prepared by the Combustion Method
(2021-01-01)
Thawong, Pichittra
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Bongkarn, Theerachai
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Jantasurin, Jirawat
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Pinitsoontorn, Supree
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Charoonsuk, Thitirat
Lead free solid solution Bi<inf>0.5</inf>(Na<inf>0.68</inf>K<inf>0.22</inf>Li<inf>0.10</inf>)<inf>0.5</inf>TiO<inf>3</inf>-xmol%Bi<inf>2</inf>FeCrO<inf>6</inf> (BNKLT-xBFCO), with x = 0, 0.004, 0.007, 0.013 and 0.019, ceramics were calcined at 750 °C and sintered at 1150 °C for 2 h using the solid state combustion technique. The effect of the x content on the phase formation, microstructure, electric and magnetic properties of the produced ceramics were investigated. All samples exhibited a pure perovskite phase with the co-existence of rhombohedral and tetragonal phases. The doping of BFCO enhanced the density and dielectric properties of the BNKLT ceramics. The BNKLT-0.013BFCO ceramics showed the highest density (5.87 g/cm3), excellent dielectric properties (ε <inf>R</inf> ∼1390, tan δ <inf>R</inf> ∼0.039, ε <inf>m</inf> ∼4986 and tan δ <inf>m</inf> ∼0.075) and the highest piezoelectric constant (d<inf>33</inf>∼194 pC/N). The sample with x = 0 showed diamagnetic behavior, while the samples with 0.004-0.019 content exhibited paramagnetic behavior with higher magnetization at higher x content.
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Apparatus for inspection of low-coercivity magnetic force microscopy tips
(2018-08-13)
Damrongsak, Badin
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Photaram, Worachote
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Saengkaew, Karnt
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Cheowanish, Ittipon
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Damrongsak, Pattareeya
In hard disk drive manufacturing, magnetic force microscopy (MFM) is employed to provide feedback for process control. This requires accurate and precise measurement of the intensity and the width of the write field generated from fabricated recording heads. Thus, the response of MFM tips when exposed to the write field must be consistency, run to run and machine to machine; however, no specific tool that can inspect and separate out-of-spec or defective MFM tips is available so far. In this present work, we designed and developed a new apparatus that is suitable to quantitatively evaluate the performance of low-coercivity MFM tips. The detailed discussion of the design of the proposed system is given as well as the inspection algorithm. Basically, a solenoid coil is used as a magnetic field generator which can generate the field strength up to 500 Oe, enough to saturate the tip magnetization. When the tip was exposed, a phase difference of the oscillating MFM tip, which is directly proportional to the field intensity, is employed as a measure of the tip response. In addition, the capability of the implemented apparatus to inspect low-coercivity MFM tips was demonstrated. Results were then compared with those obtained from a conventional MFM machine with the reference magnetic write head as a test sample. Several tests with different sets of low-coercivity MFM tips were carried out to evaluate the implemented system. Results showed that it can distinguish the response of different MFM tips; however, as the results were not too different, only three samples were selected to present here, including the tips with typical magnetic response, low response and out-of-spec response. The measured phase shifts of those samples were 54.5 ± 0.3, 36.3 ± 0.3 and 15.4 ± 0.2 degrees, respectively.
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