Article
Materials Science, Ceramics
Lin Zhou, Mingjia Jiang, Yaqiong Sun, Dong Yang, Jinhua Xu, Zhanhui Peng, Di Wu, Lingling Wei, Pengfei Liang, Xiaolian Chao, Zupei Yang
Summary: In this study, various (Cu0.5W0.5)xTi1-xO2 (CWTOx) ceramics were fabricated by a traditional solid reaction method, showing a high permittivity (epsilon r>104), low dielectric loss (tan delta < 0.1), and good temperature stability within a broad frequency/temperature range for CWTO0.015 ceramic, which meets the application requirement of X8R. Abnormal dielectric relaxation phenomena at low and high temperature regions were explained by interface polarization and ionization of oxygen vacancies, respectively, and the CP performance of CWTOx ceramics was predominantly influenced by the interface barrier layer capacitance effect according to complex impedance, XPS, and EPR results. This finding is expected to promote the further development and application of CP materials.
CERAMICS INTERNATIONAL
(2023)
Article
Materials Science, Ceramics
Yuechan Song, Peng Liu, Wenwen Wu, Quan Zhou
Summary: Al0.15Nb0.15Ti0.7O2 ceramics were synthesized via strong magnetic field alignment at 6 T and sintered under a nitrogen atmosphere. A ceramic prepared at 6 T by polishing it along the direction parallel to the magnetic field (parallel-6 T) with a brick-layered microstructure shows a colossal permittivity of ?r ?8.2 ? 104 and a low dielectric loss of tan ? ?0.019 at 1 kHz, with impedance spectroscopy suggesting that the colossal permittivity is attributed to internal barrier layer capacitor effects. XRD results indicate that approximately 90 % of the grains are aligned along the magnetic field with a tilt angle less than 10?. The average width and length of the grains for parallel-6 T ceramics are 4.1 ?m and 9.4 ?m. Compared to non-magnetically treated Al0.15Nb0.15Ti0.7O2 ceramics, the high grain boundary resistance (1.6 ? 108 ? cm) of the parallel-6 T ceramic can be responsible for this low dielectric loss.
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
(2021)
Article
Materials Science, Multidisciplinary
Lin Zhou, Zhanhui Peng, Jie Zhu, Qiangqiang Shi, Pengfei Liang, Lingling Wei, Di Wu, Xiaolian Chao, Zupei Yang
Summary: Dense (Ag2/5Mo3/5)(x)Ti1-xO2 ceramics (AMTOx) with good dielectric properties and superior temperature stability were successfully prepared. The AMTO(0)(.0125) ceramics exhibited a giant permittivity and met the application temperature requirement of Z9R capacitor. Different dielectric relaxation behaviors at low and high temperatures were explained by the interface polarization and ionization or displacement of oxygen vacancies, respectively.
MATERIALS CHEMISTRY AND PHYSICS
(2023)
Article
Materials Science, Ceramics
Rui Gu, Xu Guo, Jingrui Kang, Ruiping Ma, Honglei Hao, Hongchen Sun, Yu Lan, Zhuo Xu, Li Jin, Xiaoyong Wei
Summary: This study investigates the colossal permittivity and low dielectric loss of SrTi0.998Nb0.002O3 ceramics synthesized under a reducing atmosphere. The presence of defect dipoles and clusters in the ceramics contribute to their ultra-dielectric properties. The SNT-H-2 ceramic exhibits high temperature and frequency stability, making it a potential candidate for the development of colossal materials.
CERAMICS INTERNATIONAL
(2022)
Article
Materials Science, Multidisciplinary
Zhanhui Peng, Jitong Wang, Xiaoping Lei, Jie Zhu, Shudong Xu, Pengfei Liang, Lingling Wei, Di Wu, Juanjuan Wang, Xiaolian Chao, Zupei Yang
Summary: Al-doped CdCu3Ti4O12 ceramics were designed with a large dielectric permittivity via a solid-state synthesis process. The decrease in dielectric permittivity and increase in dielectric loss upon Al doping are strongly associated with decreased grain boundary resistance. The internal barrier layer capacitor dielectric mechanism was regarded as the origin of the colossal dielectric behaviors.
MATERIALS CHEMISTRY AND PHYSICS
(2021)
Article
Chemistry, Physical
Kai Zhang, Lingxia Li, Menglong Wang, Weijia Luo, Wenbo Wang
Summary: By adjusting donor ions doping and the distribution of oxygen vacancies, BaTiO3 ceramics with colossal permittivity and high insulation resistivity can be achieved, providing a technical basis for the preparation of single-layer microchip capacitors.
JOURNAL OF ALLOYS AND COMPOUNDS
(2021)
Article
Engineering, Electrical & Electronic
Longhai Yang, Wenjie Gao, Jiaxing Wang, Chunxiang He, Gaili Yue, Tao Zhang
Summary: Li-doped Bi2/3Cu3Ti4O12 ceramics were successfully prepared, and the effect of Li doping on the crystal structure and dielectric properties was investigated. Li doping improved the dielectric constant and reduced the dielectric loss in the mid-frequency range. The dielectric response at different frequencies was found to originate from different regions within the ceramics.
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
(2023)
Article
Materials Science, Multidisciplinary
Shilpa Kumari, Shweta Thakur, Dipika Nanda, Radheshyam Rai, Pawan Kumar, Rashmi Rani, Ratnamala Chatterjee
Summary: Polycrystalline samples of La0.665Bi0.33Ba0.005GdxMn1-xO3 were prepared and their structural and electrical properties were studied. The results showed that the samples had different crystal structures and grain sizes. The dielectric constant exhibited frequency-dependent behavior, and the materials displayed negative temperature coefficient of resistance.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2022)
Article
Materials Science, Ceramics
Lingxia Li, Jialing Xie, Menglong Wang, Kai Zhang
Summary: The study investigates the performance of Mg and Nb co-doping BaTiO3 ceramics, and suggests that appropriate MgO doping can enhance grain boundary resistance and improve dielectric properties.
CERAMICS INTERNATIONAL
(2021)
Article
Materials Science, Multidisciplinary
Ku Noor Dhaniah Ku Muhsen, Rozana Aina Maulat Osman, Mohd Sobri Idris
Summary: This study investigates the dielectric behavior and microstructural analysis of (Nb, La) co-doped TiO2 ceramic. The presence of secondary phase LaNbTiO6 affects the properties of the ceramic, and different materials and sintering temperatures lead to different results.
APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING
(2022)
Article
Chemistry, Physical
Jiangtao Fan, Yimeng Chen, Zhen Long, Liping Tong, Gang He, Zhanggui Hu
Summary: In this work, Tm + Ta co-doped TiO2 ceramics with ultrahigh permittivity and very low loss were prepared using a solid-state reaction method. The high dielectric constant and low dielectric loss were attributed to the electron pinned defect dipole response formed by the coupling of Ti3+ and oxygen vacancies. The impedance analysis and frequency dependent dielectric constant under a DC bias suggested that the internal barrier layer capacitance response and electrode response also contribute significantly to the dielectric constant.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2022)
Article
Materials Science, Ceramics
Haowen Liu, Ateer Bao, Jun Zhang, Yaohang Gu, Xiaoyan Zhang, Xiwei Qi
Summary: A new kind of high-entropy rare earth garnet ceramics was successfully synthesized by solid state reaction. The increase of Al content leads to the decrease of relative dielectric constant and the increase of dielectric loss. The activation energies of grain boundary and grain electrical conductivities indicate that the difference between them enhances the dielectric properties. These findings provide important insights for the study of colossal dielectric materials.
CERAMICS INTERNATIONAL
(2023)
Article
Nanoscience & Nanotechnology
Xian Zhang, Yongping Pu, Lei Zhang, Jinbo Zhang, Yating Ning, Yangchao Shang, Xiang Lu, Xuqing Zhang
Summary: In this study, high-performance Sr1-xErxTiO3 ceramics were successfully prepared by adjusting the sintering atmosphere. The ceramic sintered in hydrogen exhibited colossal permittivity, ultralow dielectric loss, and excellent frequency and temperature stability. The outstanding properties of these ceramics were attributed to the defect dipoles and defect clusters, as revealed by various analysis techniques.
ACS APPLIED MATERIALS & INTERFACES
(2022)
Article
Materials Science, Ceramics
Yuhui Wan, Fulin Cao, Jiachen Song, Ningjing Hou, Pengrong Ren, Fuxue Yan, Xu Lu, Ming Ma, Kexin Song, Gaoyang Zhao
Summary: This article introduces a new dielectric material BNT-xNN-SNN for high-temperature capacitors. The research shows that the BNT-0.25NN-SNN ceramic has stable dielectric properties and a high resistivity, making it suitable for high-temperature capacitors.
CERAMICS INTERNATIONAL
(2022)
Article
Chemistry, Physical
Qiyuan Zhou, Fudong Zhang, Qizhen Chai, Yan He, Zhanhui Peng, Di Wu, Pengfei Liang, Lingling Wei, Juanjuan Wang, Xiaolian Chao, Zupei Yang
Summary: This study focuses on improving the temperature stability of lead-free Bi0.5Na0.5TiO3 (BNT) ceramics by adding CaSnO3 (CS), which resulted in an excellent temperature stability and low dielectric loss for the optimal composition BNT-0.15CS.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Materials Science, Ceramics
Canglong Li, Yang Qiu, Godfrey Okumu Barasa, Songliu Yuan
CERAMICS INTERNATIONAL
(2020)
Article
Engineering, Electrical & Electronic
Jia Zheng, Qingshan Fu, Xinghan Chen, Chiranjib Chakrabarti, Pengjian Wang, Hongxia Yin, Canglong Li, Yang Qiu, Songliu Yuan
Summary: The polycrystalline Er3Fe5O12 ceramic sample synthesized using a solid-state reaction technique exhibited a colossal dielectric constant over a wide temperature and frequency range. The dielectric relaxation in the sample was found to be triggered by the dipolar effect and the Maxwell-Wagner effect at different frequencies, with possible contributions from oxygen vacancies and grain boundaries at high temperatures.
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
(2021)
Article
Materials Science, Ceramics
C. L. Li, S. S. Zheng, G. O. Barasa, Y. F. Zhao, L. Wang, C. L. Wang, Y. Lu, Y. Qiu, J. B. Cheng, Y. S. Luo
Summary: The study reveals that the heavy rare-earth orthoferrites exhibit spin reorientation transitions at different temperatures, as well as field-sensitive antiferromagnetic states, which make them potentially useful for spintronic devices.
CERAMICS INTERNATIONAL
(2021)
Article
Materials Science, Ceramics
B. Meng, Q. S. Fu, C. L. Li, X. H. Chen, Y. Qiu, S. L. Yuan
Summary: The crystal structure, magnetic properties, and magnetic exchange interactions of Fe3+-substituted Ca2NdCr2-xFexNbO9 single-phase perovskites were systematically studied. The samples exhibited an orthorhombic structure, and tunable negative magnetization phenomena were observed within a specific substitution range. Furthermore, the potential applications of magnetocaloric effect and magnetic switching effect were investigated.
CERAMICS INTERNATIONAL
(2022)
Article
Chemistry, Physical
Y. Qiu, S. S. Zheng, C. L. Li, G. O. Barasa, M. L. Chen, L. Wang, Y. F. Zhao, Y. Lu, Y. S. Luo
Summary: The effect of annealing temperature on the crystalline structure and magnetic behaviors of Co(Cr0.9Fe0.1)(2)O-4 with cubic spinel structure was experimentally investigated. The results showed that the average crystallite size increased with the annealing temperature. Samples with larger crystallite size exhibited magnetic compensation effect and negative magnetization, while the phenomena were absent in samples with smaller crystallite size. Magnetization reversal occurred at the compensation temperature under a higher magnetic field.
JOURNAL OF ALLOYS AND COMPOUNDS
(2022)
Article
Physics, Applied
B. Meng, X. T. Ji, X. H. Chen, Q. S. Fu, C. L. Li, C. Chakrabarti, Y. Qiu, S. L. Yuan
Summary: Negative magnetization effect is observed in quasi-two-dimensional distorted honeycomb-layered Ni4Nb2O9 ceramics. Different degrees of distortion lead to two types of temperature dependence in the Ni-Ni honeycomb layers with antiferromagnetic interlayered coupling, resulting in the occurrence of negative magnetization effect. This study provides a new understanding of the mechanism and potential applications of negative magnetization effect in these materials.
JOURNAL OF LOW TEMPERATURE PHYSICS
(2022)
Article
Chemistry, Inorganic & Nuclear
Godfrey Okumu Barasa, Celline Awino, Canglong Li, John Onyango Agumba, Kevin Otieno Okoth, Denis Magero
Summary: This study developed indium-modified nanoporous silver using the alloying-dealloying technique. The microstructure of the material was characterized before and after the reaction, revealing a shift of d-band centers in Ag-In that enhanced its catalytic activity. The np-Ag-In showed improved Faraday efficiency and geometric current density in CO2 reduction, attributed to synergy effects through tuning of properties and surface composition restructuring.
SOLID STATE SCIENCES
(2022)
Article
Materials Science, Ceramics
Canglong Li, Shuangshuang Zheng, Yang Qiu, Qiankun Lei, Chunlei Wang, Yang Lu, Ya Yang, Hailong Yan, Yongsong Luo
Summary: In this study, double perovskite oxides Gd2NiMn1-xTixO6 were synthesized and their structural, magnetic, and cryogenic magnetocaloric properties were investigated. It was found that Ti substitution in Gd2NiMn1-xTixO6 progressively suppressed the ferromagnetic phase due to the dilution effect. The calculated values of magnetic entropy change and refrigeration capacity showed a similar trend, decreasing first and then increasing with increasing x, indicating the potential of Gd2NiMn1-xTixO6 for magnetic refrigeration applications.
CERAMICS INTERNATIONAL
(2023)
Article
Materials Science, Multidisciplinary
S. S. Zheng, C. L. Li, C. X. Bai, K. X. Zhou, P. Wang, Y. Lu, Y. Qiu, Y. S. Luo
Summary: The present study investigates the effects of Ti substitution on the monoclinic double perovskites Gd2CoMn1-xTixO6. It is found that Ti substitution significantly suppresses the ferromagnetic transition and enhances the magnetic entropy change of the material. The study proposes a possible mechanism based on magnetic phase transition for the enhanced cryogenic magnetocaloric effect.
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS
(2022)
Article
Materials Science, Ceramics
Canglong Li, Wenqian Yang, Shuangshuang Zheng, Godfrey Okumu Barasa, Pei Wang, Kexin Zhou, Chunxu Bai
Summary: Experimental investigations on Gd2Co0.5Mn1.5O6 reveal the intrinsic effects of magnetic compensation and negative magnetization. The excessive ratio of Mn in Gd2Co0.5Mn1.5O6 leads to antisite disorder and the generation of magnetic clusters with spin glass properties. These clusters provide additional pinning force to prevent the alignment of spins with the applied magnetic field.
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
(2023)
Article
Energy & Fuels
Shuangshuang Liang, Congcong Liu, Haibin Sun, Canglong Li, Minghai Feng, Shasha Gao, Shenghong Liu, Haiyang Pan, Guixian Ge
Summary: The development of advanced electrode materials through structure engineering is of great interest for high-power and high-energy-density storage devices. In this study, a series of hierarchical Ni3SnxS2-x nanomaterials are synthesized using a feasible hydrothermal method, showing an interesting structural evolution from Ni3S2 to Ni3Sn2 through Sn doping. The optimized Ni3SnxS2-x exhibits high capacitance and excellent rate performance, attributed to the synergetic effect of numerous electrochemical active sites introduced by Sn doping and improved conductivity due to the hierarchical structure. Furthermore, the as-prepared Ni3SnxS2-x also demonstrates higher coercivity and lower saturation magnetization. This work showcases an effective approach to prepare functional electrode materials for energy storage devices.
JOURNAL OF ENERGY STORAGE
(2023)
Article
Physics, Applied
Canglong Li, Wenqian Yang, Yang Lu, Ya Yang, Chunlei Wang, Qiankun Lei, Yang Qiu, Yongsong Luo
Summary: The present experiments show that inverse exchange bias and negative magnetization can be observed simultaneously in Gd(2)Co(0.5)Mn(1.5)O(6) below the ferrimagnetic compensation point T-comp. The slower relaxation of frozen spins compared to rotatable spins confirms the intrinsic nature of the inverse exchange bias. The amplitude of the exchange bias field (H-EB) is inversely proportional to the cooling field (H-cool), and the inverse exchange bias is observed up to 50 kOe. The observed exchange bias can be attributed to the flipping of inverse ferromagnetic moments below T-comp by adjusting the amplitude or direction of the applied magnetic field.
APPLIED PHYSICS LETTERS
(2023)
Article
Materials Science, Multidisciplinary
Canglong Li, Wenqian Yang, Shuangshuang Zheng, Godfrey Okumu Barasa, Yang Qiu, Chunxu Bai
Summary: The magnetic properties of Gd(2)Co(2-x)MnxO(6) were experimentally investigated by modulating the proportion of Mn. The results showed an intrinsic effect of negative magnetization (NM) for samples with x = 1.1 to 1.5, characterized by M-FC < 0 under moderate positive cooling fields H(cool). The manipulation of magnetization states from positive to negative and vice versa, with high repeatability, stability, and controllability, through magnetic field or temperature-assisted switching effects, exhibits promising applications in spintronic devices.
Article
Chemistry, Physical
Canglong Li, Chunlei Wang, Qiankun Lei, Godfrey Okumu Barasa, Qingshan Fu, Yang Qiu
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2020)
Article
Chemistry, Physical
Q. S. Fu, X. H. Chen, C. Chakrabarti, C. L. Li, J. Zheng, P. J. Wang, H. X. Yin, Y. Qiu, B. Meng, S. L. Yuan
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2020)