Journal Pre-proof Synthesis of V2O5-Doped and low-sintered NiCuZn ferrite with uniform grains and enhanced magnetic properties Xueying Wang, Dainan Zhang, Gang Wang, Lichuan Jin, Jie Li, Yulong Liao, Huaiwu Zhang, Shiyuan Wang PII:
S0272-8842(20)30071-7
DOI:
https://doi.org/10.1016/j.ceramint.2020.01.071
Reference:
CERI 24003
To appear in:
Ceramics International
Received Date: 12 April 2019 Revised Date:
6 January 2020
Accepted Date: 9 January 2020
Please cite this article as: X. Wang, D. Zhang, G. Wang, L. Jin, J. Li, Y. Liao, H. Zhang, S. Wang, Synthesis of V2O5-Doped and low-sintered NiCuZn ferrite with uniform grains and enhanced magnetic properties, Ceramics International (2020), doi: https://doi.org/10.1016/j.ceramint.2020.01.071. This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. © 2020 Published by Elsevier Ltd.
Synthesis of V2O5-Doped and Low-Sintered NiCuZn Ferrite with Uniform Grains and Enhanced Magnetic Properties Abstract NiCuZn ferrites with high permeability and low magnetic loss have great application potential in high-frequency electronics. In this study, the excellent magnetic properties of (Ni0.2Cu0.2Zn0.6O)1.03(Fe2O3)0.97 ferrites are explored by doping low-melting point V2O5. The results demonstrate that the introduction of V2O5 can promote grain growth, reduce pores between grains, and obtain a denser microstructure of NiCuZn ferrites. NiCuZn ferrites with high permeability (µ’≈693.2), high saturation magnetic flux density (Bs=325.1 mT), high remanence (Br=174.3 A/m), high Q value (~47.60), and low coercivity (Hc=69.06 A/m) are obtained when the samples are sintered at 900 °C. However, when excessive V2O5 is added, the presence of the non-magnetic V2O5 liquid phase weakens the magnetic properties and deteriorates the grain uniformity. A dense and uniform NiCuZn ferrite sample with excellent magnetic properties can be obtained by doping 0.50 wt.% V2O5. The results indicate that V2O5 can be a good candidate for low-temperature sintering. Keywords: NiCuZn ferrites, grain growth, V2O5 doping, magnetic property, microstructure Introduction The rapid development of electronic information industry and communication technology has led to the continuous development of high frequency, miniaturized, and integrated modern electronic devices. Fortunately, ceramic ferrite with good electrical properties and appropriate magnetic performance is an ideal oxide material suitable for the preparation of electronic components [1-7]. High-permeability and low-loss NiCuZn ferrites can be applied to the preparation of power inductors, which play a major role in DC-DC converter modules [8]. In general, inductors consisting of non-magnetic cores are affected by low inductance and large size [9]. To overcome this shortcoming, NiCuZn ferrites can be used to prepare high-performance power inductors. Additives and sintering conditions have profound effects on the microstructure and magnetic properties of ferrites. A lot of research has been
conducted to achieve the desired material properties [10-13]. Luo et al. obtained a sample with low power loss by doping 0.25 wt.% Bi2O3 into NiCuZn ferrite, which can be used in chip power magnetic devices or modules [14]. However, Ag diffuse into ferrites at high sintering temperature, and internal conductor resistivity increases. The segregation of Cu induced by Ag diffusion leads to the deterioration of magnetic properties. For NiCuZn ferrites, a small grain size may result in low permeability and high coercivity [15]. Therefore, it is essential to promote the progress of the solid phase reaction at lower temperature. Xu et al. reduced the sintering temperature by adding Bi2O3-Nb2O5 composite additive, thus improving the densification of NiCuZn ferrites [16]. In general, the introduction of additives is a practical solution. V2O5 is often used as an additive due to its essential industrial value with low melting temperature (approximately 690 °C). By adding V2O5, the grain boundary of ferrites is well formed during the sintering process, thereby promoting grain growth [17,18]. Xu et al. controlled the movement of the grain boundary using the viscous flowing liquid phase of V2O5 in the sintering stage, and obtained uniform LiZn ferrite with high saturation magnetization and low ferromagnetic resonance line width [19]. In this work, V2O5 additive was introduced to lower the sintering temperature of NiCuZn ferrites. The influence of different proportions of additives (x=0.00, 0.25, 0.50, and 0.75) on the grain growth, grain size, microstructure, and magnetic properties of NiCuZn ferrites was explored. Finally, a dense and uniform NiCuZn ferrite sample was compounded at low temperature. Experiment The composite (Ni0.2Cu0.2Zn0.6O)1.03(Fe2O3)0.97 ferrite was prepared via conventional solid-state reaction. Pure powders of NiO (99%), ZnO (99%), CuO (99%), and Fe2O3 (99%) were weighed and mixed with deionized water. The mixtures were ball-milled at a rotational speed of 250 rpm for 4 h in a planetary ball mill (Nanjing Machinery Factory, Nanjing China). They were then dried and pre-sintered in an air atmosphere at 800 oC for 2 h. Afterwards, 0.00 wt.%, 0.25 wt.%, 0.50 wt.%, and 0.75 wt.% V2O5 powders were respectively added to the powders for low-temperature sintering. After the second ball-milling for 6 h, the mixtures were dried for granulation with 10 wt.% PVA added as a binder. The particles were then
pressed into rings and wafers at a pressure of 8 MPa. Finally, the samples were sintered at 900 oC in a furnace. Diffraction peaks of the samples were tested by an X-ray diffractometer (XRD, Miniflex 600, Rigaku, Japan), λ=1.5405 Å in a θ-2θ geometry with a step scan of 0.02o, 5o per minute with 20o<2θ<70o Cu-Kɑ radiation. An RF impedance analyzer (E4991B, Agilent) was employed to measure the magnetic and dielectric spectra. The saturation flux density (Bs), remanence (Br), and coercivity force (Hc) were measured using an Iwatsu BH analyzer (SY8232) in an alternating field 1600 A/m at 1 kHz. SEM images were obtained using a scanning electron microscope (SEM, JSM-6490, JEOL, Japan). The Archimedes method was adopted to measure the bulk densities in distilled water. All of the tests were conducted at room temperature. Results and discussion The XRD patterns of different V2O5-doped NiCuZn ferrites sintered at 900 oC are shown in Fig. 1. The crystal plane indexes of the corresponding diffraction peaks are indicated. The refinement results of the ferrite ceramics are shown in Fig. 2 and Table 1. Low Rwp and Rp values denote high reliability of the refinement results, which is consistent with the XRD diffraction patterns. All samples display single-phase spinel structures with any V2O5 additives, indicating the samples contain only the spinel phase and no secondary phase [20-22]. The results demonstrate that no reaction occurred between the V2O5 and NiCuZn ferrites in the sintering process [23,24]. In other words, adding a small amount of V2O5 (less than 0.75 wt.%) cannot influence the formation of the spinel phase polycrystalline NiCuZn ferrites at the sintering temperature [25].
Fig. 1. XRD patterns of the proposed samples sintered at 900 °C with different V2O5 additives (x=0.00, 0.25, 0.50, and 0.75).
Fig. 2. Rietveld refinement of the NiCuZn ferrites sintered at 900 °C with different V2O5 additives (x=0.00, 0.25, 0.50, and 0.75). Table 1. Rietveld refinement parameters of the NiCuZn ferrite ceramics with different V2O5 additive amounts x (wt.%)
0.00
0.25
0.50
0.75
Lattice constant (Å)
8.41
8.41
8.40
8.4070
Rwp
3.28%
2.91%
2.89%
2.32%
Rp
1.96%
1.83%
1.82%
1.57%
The microstructures of the samples with different additives are shown in Fig. 3. The particle size and density of pores change significantly with the increase in V2O5 content. When V2O5 is not added, the average particle size is small, and the number of pores is large, indicating the samples have low density. As the V2O5 increases, the particle size grows and the number of pores decreases, causing better uniformity. When the addition ratio is 0.75 wt.% (as shown in Fig. 3d), as reflected in the SEM image, the particle size continues to increase, and the sample becomes denser.
Meanwhile, some abnormal crystal particles emerge, and the uniformity deteriorates. These phenomena may be resulted from the transferring of additive V2O5 to the liquid phase during the sintering process, the uniform flow into the grain boundaries of the NiCuZn ferrite particles and the filling of the pores. Liquid with good wettability can reduce the friction coefficients between particles and promote the movement and alignment of grains during the sintering process. Small crystal grains in the samples preferentially infiltrate and dissolve in the liquid phase. When the solubility reaches saturation, the particles in the liquid phase are separated and precipitated on large particles, which is conductive to the grain growth and resulting in decreased pores and uniform structure. However, if too much V2O5 is added, the lower solid-liquid interface can reduce the activation energy of the whole system, leading the annexation process between grains, forming abnormal crystal grains and deteriorating the homogeneity [26]. Energy-dispersive X-ray (EDX) spectra were recorded for the NiCuZn ferrite samples with different amounts of V2O5. All of the elements, including nickel, copper, zinc, iron, and oxygen of ferrite, are shown in Fig. 4. These spectra demonstrate that no impurity elements appeared. (a)
(b)
(c)
(d)
Fig. 3. SEM images of the samples with various V2O5 additives. (a) 0.00 wt.%, (b) 0.25 wt.%, (c) 0.50 wt.%, and (d) 0.75 wt.%.
(a) (a)
(b) (b)
(c)
(d)
Fig. 4. X-ray (EDX) spectra of the NiCuZn ferrite samples with different amounts of V2O5. (a) 0.00 wt.%, (b) 0.25 wt.%, (c) 0.50 wt.%, and (d) 0.75 wt.%. Table 2 shows the variations in the experimental density of the samples sintered at 900 ℃ with different additive amounts of V2O5. The density initially increased as the V2O5 content increased from 5.00 to 5.22. Since the liquid phase promoted grain growth and densification during the sintering process, the density decreased with excessive V2O5 addition[27,28]. Subsequently, because the density of V2O5 was much smaller than that of NiCuZn ferrites, the excess additive causes a slight decrease in the density of samples with 0.75 wt.% additives [29,30]. Table 2. Parameters of the NiCuZn ferrites with different amounts of V2O5 sintered at 900 oC V2O5 (wt.%)
0.00
0.25
0.50
0.75
Density (g/cm3)
5.00
5.11
5.22
5.18
Bs (mT)
246.5
306.1
325.1
298
Br (mT)
153
172.8
174.3
134.1
Q factor
35.19
47.60
41.93
25.35
Hc (A/m)
120.4
73.15
69.06
86.96
Fig. 5 shows the magnetic spectra of the proposed NiCuZn ferrites calcined at 900 oC with different amounts of V2O5 additive. The real part (µ') of the magnetic permeability first increased and then decreased. When the additive amount of V2O5
was 0.5, the value of µ' was the largest. The reason for this phenomenon may be that the magnitude of permeability is closely related to the grain size of polycrystalline ferrite materials. The decrease in the grain size significantly reduces the contribution of the domain wall motion to the magnetic permeability [31,32]. Additionally, small grains mean more grain boundaries in the crystal, thereby impeding magnetic domain movement and reversible displacement [33-35]. Therefore, the ferrites without additive had low permeability. When excess V2O5 (0.75 wt.%) was introduced, non-magnetic ion diffusion impaired the contribution of the ferrites to the permeability, which explained why µ' decreased [36-38].
Fig. 5. Magnetic spectra of the NiCuZn ferrites with various V2O5 additives. The remanence (Br) displayed in Fig. 6 shows that Br first increased as the V2O5 content increased from 0.00 wt.% to 0.50 wt.% and then decreased significantly as the V2O5 content increased to 0.75 wt.%. When V2O5 was not added, the solid phase reaction was insufficient. The SEM image demonstrates that the average particle size was small and there were many pores between the particles, thus decreasing the overall magnetic moment and remanence Br of the material. An appropriate amount of sintering aid promoted the solid phase reaction and promoted the growth of the crystal grains. The pores were discharged from the grain boundaries, and the value of Br increased. Meanwhile, when the additive was 0.5 wt.%, Br reached a maximum value of approximately 175. As the amount of addition continued to increase, the rapid growth of the grains deteriorated the grain uniformity and decreased Br [39].
The saturation flux density (Bs) of the NiCuZn ferrites is shown in Fig. 6. It increased first and subsequently decreased as the additive amount of V2O5 increased. Luo. et al. concluded that Bs can be affected by porosity and density [14,16]. Additional V2O5 changed the porosity and introduced excess non-magnetic additive, which might have weakened the contribution of the magnetic NiCuZn ferrite grains to the magnetic moment per unit volume. By adding 0.5 wt.% V2O5, the maximum Bs value (~325.1 mT) was obtained [40,41].
Fig. 6. Variations in the saturation flux density (Bs) and the remanence (Br) of the NiCuZn ferrites with different V2O5 additives. As can be seen from Fig. 7, the Q factor of the NiCuZn ferrites with different V2O5 concentrations at 1 MHz. When the concentration of V2O5 was 0.25 wt.%, uniform microstructure samples with a small average grain size and the highest Q factor were obtained. Afterward, the Q value decreased significantly when the additives were continuously introduced, which may be caused by the deterioration of the homogeneity and the increase in the permeability of the imaginary part. Also, Fig. 7 shows that the variation of Hc was opposite to that of Bs. It decreased first and subsequently increased as the additive amount of V2O5 increased. This is mainly determined by the variations in the grain size [42,43]. The smaller the grain size of the ferrite, the more the grain boundaries in a unit volume. Therefore, there are more pinning positions which can hinder the movement of the domain walls [44]. That is to say, more energy is required to move the domain walls, and thus Hc is
higher. However, the liquid phase appeared in the grain boundary as more than 0.50 wt.% of V2O5 was doped, leading to an increase in Hc [45].
Fig. 7. Changes in the Q values of the NiCuZn ferrites at 1.0 MHz and the coercivity (Hc) of the NiCuZn ferrites with different V2O5 additives. As shown in Fig. 8, the saturation magnetization curves of the four samples sintered at 900 oC were obtained through a bias field of -5000 to +5000 Oe. Table 3 indicates that the optimized addition volume of NiCuZn with high saturation magnetization (~3357 gauss) is 0.5 wt.%. The results prove that the optimized additive can not only improve the microstructure, but also enhance the magnetic properties.
Fig. 8. Variations in the specific saturation magnetization of the NiCuZn ferrite ceramics sintered at 900 °C.
Table 3. Magnetic properties of the NiCuZn ferrite ceramics sintered at 900 °C
0.00
50.52
3174.27
0.25
50.01
3211.35
0.50
51.18
3357.23
0.75
49.37
3213.68
Conclusion In this study, the effects of V2O5 additives on the microstructure and magnetic properties of NiCuZn ferrites sintered at 900 oC were discussed in detail. When 0.50 wt.% V2O5 was added, the µ' value of the samples reached 693.19, and the Q value was 41.9 at 1 MHz. Bs reached a maximum value of 325.1 mT, and the coercive force decreased to 69.06 A/m. The microstructure and magnetic properties demonstrate that compact NiCuZn ferrites with enhanced magnetic properties were synthesized due to the V2O5 liquid phase between the grains. These results indicate that V2O5 is a good additive for the preparation of NiCuZn at low sintering temperature.
Conclusion In this study, the effects of V2O5 additives on the microstructure and magnetic properties of NiCuZn ferrites sintered at 900 oC were discussed in detail. When 0.50 wt.% V2O5 was added, the µ' value of the sample reached 693.19 and the Q value was 41.9 at 1 MHz. Bs reached a maximum value of 325.1 mT, and the coercive force decreased to 69.06 A/m. These microstructure and magnetic properties results demonstrated that due to the V2O5 liquid phase between the grains, compact NiCuZn ferrites with enhanced magnetic properties were synthesized. These results indicated that V2O5 was a good choice as an additive for the preparation of NiCuZn at low sintering temperatures. Acknowledgments
This work was financially supported by the National Key Scientific Instrument and Equipment Development Project (No. 51827802), the National Key Research and Development Plan (No. 2016YFA0300801), and the National Nature Science Foundation of China (No. 61021061 and No. 61271037). Figure and table captions Fig. 1. XRD patterns of the proposed samples sintered at 900 °C with different V2O5 additives (x=0.00, 0.25, 0.50, and 0.75). Fig. 2. Rietveld refinement of the NiCuZn ferrites sintered at 900 °C with different V2O5 additives (x=0.00, 0.25, 0.50, and 0.75). Fig. 3. SEM images of the samples with various V2O5 additives. (a) 0.00 wt.%, (b) 0.25 wt.%, (c) 0.50 wt.%, and (d) 0.75 wt.%. Fig. 4. X-ray (EDX) spectra of the NiCuZn ferrire samples with different amounts of V2O5. (a) 0.00 wt.%, (b) 0.25 wt.%, (c) 0.50 wt.%, and (d) 0.75 wt.%. Fig. 5. Magnetic spectra of the NiCuZn ferrites with various V2O5 additives. Fig. 6. Variations in the saturation flux density (Bs) and the remanence (Br) of the NiCuZn ferrites with different V2O5 additives. Fig. 7. Changes in the Q values of the NiCuZn ferrites at 1.0 MHz and the coercivity (Hc) of the NiCuZn ferrites with different V2O5 additives. Fig. 8. Variations in the specific saturation magnetization of the NiCuZn ferrite ceramics sintered at 900 °C. Table captions Table 1. Rietveld refinement parameters of the NiCuZn ferrite ceramics with different V2O5 additive amounts Table 2. Parameters of the NiCuZn ferrites with different amounts of V2O5 sintered at 900 oC
Table 3. Magnetic properties of the NiCuZn ferrite ceramics sintered at 900 °C
REFERENCES [1] Gongwen Gan, Huaiwu Zhang, Qiang Li, Jie Li, Xin Huang, Fei Xie, Fang Xu, Low loss, enhanced magneto-dielectric properties of Bi2O3 doped Mg-Cd ferrites for high frequency antennas, J. Alloys. Compounds. 735 (2018) 2634-2639. [2] Min-Gon Lee, Sung-Yoon Chung, Suk-Joong L.Kang, Boundary faceting-dependent densification in a BaTiO3 model system, Acta. Mater. 59 (2) (2011) 692-698. [3] Chung-Ru Wu, Hsieh-Hung Hsieh, Liang-Hung Lu, An Ultra-Wideband Distributed Active Mixer MMIC in 0.18-µm CMOS Technology, IEEE Trans. Microw. Theory Tech. 55 (4) (2007) 625 - 632. [4] Lathiya, Poonam, Wang, Jing, Effects of the Sintering Temperature on RF Complex Permeability of NiCuCoZn Ferrites for Near-Field Communication Applications, IEEE Trans. Magn. 55(2) (2019). [5] Weihu Liu, Hongshuai Jia, Zhizhi Zhang, Fu Chen, Hui Luo, Zekun Feng, Xian Wang, Monodomain NiCuZn Ferrite With High Miniaturization Factor and Low Magnetic Loss at 200 MHz for Antenna Miniaturization, IEEE Trans. Magn. 53(12) (2017). [6] Shuoqing Yan, Weihu Liu, Zhongyan Chen, Yan Nie, Xian Wang, and Zekun Feng, Preparation and characterization of ferrite with Co substituted NiCuZn sheets application for 13.56 MHz radio frequency identification communication, J. Appl. Phys. 7115 (17) (2014) [7] Weihu Liu, Shuoqing Yan, Yongzhi Cheng, Monodomain Design and Permeability Study of High-Q-Factor NiCuZn Ferrites for Near-Field Communication Application, J. Electron. Mater. 44 (11) (2015) 4367-4372. [8] Li, Yuanxun, Yunsong Xie, Ru Chen, Likun Han, Daming Chen, Hua Su, A multilayer power inductor fabricated by cofirable ceramic/ferrite materials with LTCC technology,
IEEE
Transactions on Components, Packaging and Manufacturing Technology 7 (9) (2017) 1402-1409. [9] Zhao, Qun, Fred C. Lee, High-efficiency, high step-up DC-DC converters, IEEE T Power. Electr. 18 (1) (2003) 65-73. [10] Weihu Liu, Shuoqing Yan, Yongzhi Chengm, Qifan Li, Enhanced gyromagnetic properties of NiCuZn ferrite ceramics for LTCC applications by adjusting MnO2-Bi2O3 substitution, Ceram. Int. 44 (16) (2018) 19370-19376. [11] Fei Xie, Lijun Jia , Fang Xu, Jie Li, Gongwen Gan, Huaiwu Zhang, Improved sintering characteristics and gyromagnetic properties of low-temperature sintered Li. 42Zn. 27Ti. 11Mn. 1Fe2. 1O4
ferrite ceramics modified with Bi2O3-ZnO-B2O3 glass additive, Ceram. Int. 44 (11)
(2018) 13122-13128. [12] Elena Lysenko , Evgeniy Nikolaev, Vitaliy Vlasov, Anatoliy Surzhikov, Microstructure and reactivity of Fe2O3-Li2CO3-ZnO ferrite system ball-milled in a planetary mill, Thermochim. Acta. 664 (2018) 100-107.
[13] Gang Wang, Huaiwu Zhang, Xin Huang, Fang Xu, Gongwen Gan, Yan Yang, Dandan Wen, Jie Li, Cheng Liu, Lichuan Jin, Correlations between the structural characteristics and enhanced microwave dielectric properties of V–modified Li3Mg2NbO6 ceramics, Ceram. Int. 44 (16) (2018) 19295-19300 [14] Qiang Luo, Hua Su, Xiaoli Tang, Ziqiang Xu, Yuanxun Li, Yulan Jing, Effects of Bi2O3 addition on power loss characteristics of low-temperature-fired NiCuZn ferrites, Ceram. Int. 44 (13) (2018) 16005-16009. [15] PengWang, XiaoliTang, HuaiwuZhang, ShengleiChe, YuanxunLi, YulanJing, Effects of Al2O3 addition on the DC--bias-superposition characteristic of the low-temperature-fired NiCuZn ferrites, 803 (2019) 812-817 [16] Fang Xu, Dainan Zhang, Gang Wang, Huaiwu Zhang, Yan Yang, Yulong Liao, Lichuan Jin, Yiheng Rao, Jie Li, Fei Xie, Gongwen Gan, Densification and magnetic properties of NiCuZn low-sintering temperature ferrites with Bi2O3-Nb2O5 composite additives, J. Alloys. Compounds. 776 (2019) 954-959. [17] P.N.Anantharamaiah, P.A.Joy, Effect of co-substitution of Co2+ and V5+ for Fe3+ on the magnetic properties of CoFe2O4, Physica. B. 554 (2019) 107-113. [18] Guohua Wu, Zhong Yu, Zhangdong Tang, Ke Sun, Rongdi Guo, Xin Zou, Xiaona Jiang, Zhongwen Lan, Effect of CaCO3 and V2O5 Composite Additives on the Microstructure and Magnetic Property of MnZn Ferrites, IEEE Trans. Magn.54 (11) (2018) 1-7. [19] Fang Xu, Huaiwu Zhang, Fei Xie, Yulong Liao, Yuanxun Li, Jie Li1, Lichuan Jin1, Yan Yang, Gongwen Gan1, Gang Wang1, Qiang Zhao, Investigation of grain boundary diffusion and grain growth of lithium zinc ferrites with low activation energy, J. Am. Ceram. Soc. 101 (11) (2018) 5037-5045. [20] Yong-Il Kim, Min Ku Jeon, Won-Bin Im, Crystal Structural Study of Ho-doped Ceria Using X-ray Powder Diffraction Data. J. Electroceram. 31(1-2) (2013) 254-259. [21] Hsing-IHsiang, Jhao-LingWu, Copper-rich phase segregation effects on the magnetic properties and DC-bias-superposition characteristic of NiCuZn ferrites, J. Magn. Magn. Mater. 374 (2015) 367-371. [22] Yao Li, Jiupeng Zhao, Jiecai Han, Xiaodong He, Combustion synthesis and characterization of NiCuZn ferrite powders, Mater. Res. Bull. 40 (6) (2005) 981-989. [23] GAO FENG, YANG ZUPEI, HOU YUDONG, TIAN CHANGSHENG, Cofiring properties and camber development of ferroelectric/ferrite multilayer composites, J. Mater. Sci. 38 (7) (2003) 1523-1528. [24] Li Jie, Zhang Huaiwu, LI Qiang, LI Yuanxun,Yu Guoliang, Influence of La-Co substitution on the structure and magnetic properties of low-temperature sintered M-type barium ferrites, J. RARE. EARTH. 31 (10) (2013) 983-987. [25] Anpeng Wang, Hua Su, Xiaoli Tang, Yuanxun Li, Zhiqiang Xu, Yulan Jing, Comparison between Nb2O5 and CaCO3 additions on the DC-bias-superposition characteristic of
low-temperature-fired NiCuZn ferrites, J. Mater. Sci: Mater. Electron. 29 (17) (2018) 14605-14611. [26] Yu Jin, Haikui Zhu, Yanqiu Xu, Yulong Jin, Zhiming Xu, Effects of Bi2O3-WO3 additive on microstructure and magnetic properties of low-temperature-fired MgCuZn ferrites, J. Mater. Sci: Mater. Electron,26 (6) (2015) 4325-4329. [27] Yulong Liao, Fang Xu, Dainan Zhang, Tinchuan Zhou, Qi Wang, Xiaoyi Wang, Lijun Jia, Jie Li, Hua Su, Low Temperature Firing of Li0.43Zn0.27Ti0.13Fe2.17O4 Ferrites with Enhanced Magnetic Properties, J. Am. Ceram. Soc. 98 (8) (2015) 2556-2560. [28] Hsing℃I Hsiang, Jui℃Fu Chueh, Bi2O3 addition effects on the sintering mechanism, magnetic properties, and DC superposition behavior of NiCuZn ferrites. Int. J. Appl. Ceram. Technol. 12 (5) (2015) 1008-1015. [29] Hua Su, Qiang Luo, Yulan Jing, Yuanxun Li, Huaiwu Zhang, Xiaoli Tang,Effects of calcination temperature and flux doping on the microstructure and magnetic properties of low-temperature-fired NiCuZn ferrites. J. Magn. Magn. Mater. 469 (2019) 419-427. [30] Gang Wang, Dainan Zhang, Yuanming Lai, Xin Huang, Yan Yang, Gongwen Gan, Fang Xu, Qianqian Wang, Jie Li, Cheng Liu, Lichuan Jin, Yulong Liao, Huaiwu Zhang,Ultralow loss and temperature stability of Li3Mg2NbO6-xLiF ceramics with low sintering temperature, J. Alloys. Compounds. 782 (2019) 370-374. [31] Sharifa Nasrin, Subrin Mostafa Khan, M. A. Matin, M. N. I. Khan, Synthesis and deciphering the effects of sintering temperature on structural, elastic, dielectric, electric and magnetic properties of magnetic Ni0.25Cu0.13Zn0.62 Fe2O4 ceramics, J. Mater. SCI-Mater. El. 30 (11) (2019) 10722-10741. [32] Hamed Bahiraei, C.K. Ong, The role of iron ions on microstructural and magnetic properties of MgCuZn ferrites prepared by sol-gel auto-combustion process, Mater. Res. Bull. 111 (2019) 195-201 [33] Qiang Zhao, Huaiwu Zhang, Jie Li, Fang Xu, Yulong Liao, Cheng Liu, Hua Su, Low-temperature sintering synthesis and electromagnetic properties of NiCuZn/BaTiO3 composite materials, J. Alloy. Compd, 788 (2019) 44-49 [34] Y. Matsuo, M. Inagaki, T. Tomozawa, F. Nakao, High performance NiZn ferrite, 37 (4) (2001) 2359 - 2361 [35] Sharmin Akter, Md. D. Rahaman, M.N.I. Khan, A.K.M. Akther Hossain, Synthesis, structural, morphological, electrical and magnetic properties of (1-x) [Ni0.35Cu0.15Zn0.50Mn0.05Fe1.95O4] + (x) [Rice husk ash] composites, Mater. Res. Bull. 112 (2019) 182-193 [36] Sea-Fue Wang, Yuh-Ruey Wang, Thomas C.K Yang, Che-Fu Chen, Chun-An Lu, Chi-Yuen Huang,Densification and magnetic properties of low-fire NiCuZn ferrites. J. Magn. Magn. Mater. 220 (2-3) (2000) 129-138. [37] M. Penchal Reddy, M. Venkata Ramana, W. Madhuri, K. Sadhana, K. V. Siva Kumar & R. Ramakrishna Reddy,Effect of sintering temperature on structural and magnetic properties of
NiCuZn and MgCuZn ferrites. J. Magn. Magn. Mater. 322 (19) (2015) 2819-2823. [38] J. Murbe, J. Topfer, Ni-Cu-Zn Ferrites for low temperature firing: II. Effects of powder morphology and Bi2O3 addition on microstructure and permeability, J. Electorceram. 16 (3) (2006) 199-205. [39] Shuoqing Yan, Lianwen Deng, Zekun Feng, Jun He, Yuhan Li, Mingzhe Hu, Effect of Co2O3 Addition on Stability of Permeability to an Impulse Magnetic Field in NiCuZn Ferrites, IEEE Trans. Magn.53 (8) (2017). [40] Wei Shen, Haikui Zhu, Yu Jin, Hongqing Zhou, Zhiming Xu, Sintering, microstructure and magnetic properties of low-temperature-fired NiCuZn ferrites doped with B2O3, Ceram. Int. 40 (7) 2014 9205-9209 [41] Fei Xie, Lijun Jia, Fang Xu, Jie Li, Gongwen Gan, Huaiwu Zhang, Improved sintering characteristics
and
gyromagnetic
properties
of
low-temperature
sintered
Li.42Zn.27Ti.11Mn.1Fe2.1O4 ferrite ceramics modified with Bi2O3-ZnO-B2O3 glass additive, Ceram. Int. 44 (11) 2018 13122-13128 [42] M. Kavanloui, B. Hashemi, Effect of B2O3 on the densification and magnetic properties of Li–Zn ferrite, Mater. Design. 32 (8-9) (2011) 4257-4261 [43] Hsing-I Hsiang, Wen-Ching Kuo, Chi-Shiung Hsi, Sintering and cooling atmosphere effects on the microstructure, magnetic properties and DC superposition behavior of NiCuZn ferrites, J. Eur. Ceram. Soc. 37 (5) (2017) 2123-2128 [44] Kaiwei Li, Ke Sun, Chuan Chen, Xin Liu, Rongdi Guo, Hai Liu, Zhong Yu, Xiaona Jiang, Zhongwen Lan, Tunable ferromagnetic resonance linewidth of cobalt-substituted NiCuZn ferrites, J. Alloy. Compd, 752 (2018) 395-401 [45] Ke Sun, Zhongwen Lan, Zhong Yu, Lezhong Li, Jiaomin Huang and Xiaoning Zhao,Grain growth, densification and magnetic properties of NiZn ferrites with Bi2O3 additive, J. Phys. D. Appl. Phys. 41 (23) (2008).
Declaration of Interest Statement The authors declared that they have no conflicts of interest to this work. We declare that we do not have any commercial or associative interest that represents a conflict of interest in connection with the work submitted.