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123 results on '"Rao Guang-Hui"'

8. Microstructures and photovoltaic effect of KNbO3–SrCo0.5Hf0.5O3−δ ferroelectric semiconductors.

Author

Su, Mingwei, Su, Qi, Deng, Tingcong, Gao, Qingyuan, Yuan, Changlai, Xiong, Jian, Liu, Xiao, Lei, Wen, Xu, Jiwen, Liu, Fei, Zhou, Changrong, and Rao, Guang Hui

Subjects
FERROELECTRICITY, FERROELECTRIC materials, PHOTOVOLTAIC effect, POTENTIAL energy, SEMICONDUCTORS, ENERGY bands, FERROELECTRIC ceramics
Abstract

Polarization is one of the unique properties of ferroelectric materials; yet the polarization mechanism for enhancing ferroelectric photovoltaic performance is rarely been investigated, particularly in terms of bandgap variation. In this work, the effect of high‐field polarization on the enhanced photovoltaic performance of a ferroelectric ceramic, 0.98KNbO3–0.02SrCo0.5Hf0.5O3−δ (KNSCH2), was explored in terms of bandgap variation. The bandgap of the KNSCH2 sample shrank after polarization because of the increase in potential energy band overlap and the upward shift of the valence band due to increased oxygen‐vacancy defects. The polarization optimized the energy band structure of KNSCH2, promoting the separation and transport of photoinduced carriers and thus further enhancing its photovoltaic performance. The KNSCH2 sample shows a twofold enhancement in Jsc after 60 kV/cm polarization. The degree of the lattice distortion of KNSNH2 increased following polarization, causing a minute increase in its cell asymmetry. The reasons for the bandgap narrowing and the creation of sub‐bandgaps in the KNSCH samples were also investigated. This work opened new doors to understanding the mechanisms underlying the polarization‐enhanced photovoltaic performance of ferroelectric materials. [ABSTRACT FROM AUTHOR]

Published
2023
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11. Achieving Ultrahigh Photocurrent Density of Mg/Mn-Modified KNbO3 Ferroelectric Semiconductors by Bandgap Engineering and Polarization Maintenance

Author

Lan, Yuchen, primary, Tang, Wenbin, additional, Yuan, Changlai, additional, Xiong, Jian, additional, Xue, Xiaogang, additional, Chen, Jun, additional, Miao, Lei, additional, Zhao, Jingtai, additional, Rao, Guang-Hui, additional, Guo, Yiping, additional, Zhou, Changrong, additional, and Peng, Biaolin, additional

Published
2022
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18. Enhanced piezoelectric and ferroelectric properties of tetragonal BiFeO3–BaTiO3 ceramics via tailoring sintering temperature and dwell time.

Author

Cheng, Shuai, Zhang, Bo-Ping, Wang, Li-Jun, Yang, Tao, Yuan, Chang-Lai, Zhou, Chang-Rong, Rao, Guang-Hui, and Yin, Yang

Subjects
SINTERING, LEAD-free ceramics, SPECIFIC gravity, STRAY currents, CERAMICS, DENSITY currents, GRAIN size
Abstract

The enhanced piezoelectric and ferroelectric properties of the tetragonal 0.67BiFeO3–0.33BaTiO3 (BF–33BT) ceramics without MnO2 doping or other dopants via tailoring sintering temperature (TS) and dwell time (td) are reported. All ceramics crystallized in a single tetragonal phase, independent of the adopted TS and td. As the TS or td is increased, the BF–33BT ceramics show an increase in grain size and in relative density, while TS > 980 °C or td > 6 h would result in more oxygen vacancies caused by Bi3+ evaporation and/or reduction of Fe3+ to Fe2+, along with a reduced relative density and an increased current leakage density. Because of the increased grain size, the higher relative density, and relatively less oxygen vacancies, high d33 = 151 pC/N and Pr = 25.9 μC/cm2 were achieved in tetragonal BF–33BT ceramics with TS = 980 °C and td = 6 h. In addition, large unipolar strain of 0.146% and d 33 ∗ =326 pm/V (40 kV/cm), as well as high TC = 427 °C were also obtained in the BF–33BT ceramics with TS = 980 °C and td = 6 h. Our studies indicate that the grain size, the relative density, and the oxygen vacancies play important roles for the piezoelectric properties of BF–33BT ceramics. [ABSTRACT FROM AUTHOR]

Published
2021
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21. Structure of LaFe9Si4 intermetallic compound

Author

Tang, Wei-hua, Liang, Jing-kui, Chen, Xiao-long, and Rao, Guang-hui

Subjects
Intermetallic compounds -- Research, Molecular structure -- Analysis, X-rays -- Diffraction, Physics
Abstract

X-ray powder diffraction study helps determine the crystal structure of LaFe9Si4, an intermetallic compound equilibrated at 1173 K, and the use of Rietveld technique helps refine the structure. The crystal has a tetragonal symmetry with space group I4/mcm, and each unit cell has four formula units of LaFe9Si4. X-ray data help determine lattice parameters and density. The structure has five types of equivalent positions.

Published
1994

22. Stabilized cubic phase BiAgSe2−xSx with excellent thermoelectric properties via phase boundary engineering.

Author

Hu, Yao, Yuan, Song, Huo, Haojie, Xing, Juanjuan, Guo, Kai, Yang, Xinxin, Luo, Jun, Rao, Guang-Hui, and Zhao, Jing-Tai

Abstract

Quaternary compound BiAgSeS shows an excellent thermoelectric performance with ultralow thermal conductivity. However, competition between the trigonal and cubic phases, which is strongly dependent on experimental processing, results in ambiguous transport behavior. The highly stable n-type polycrystalline BiAgSe2−xSx (x = 1.2) sample was successfully synthesized, guided by phase boundary engineering. Whilst maintaining promising thermoelectric properties, significant enhancement of the thermodynamical stability was obtained due to the strengthened chemical bonding caused by the substitution of Se with high-electronegativity S. Cubic BiAgSe0.8S1.2 can be well preserved after thermoelectric measurements. Our work demonstrates that phase boundary engineering is an applicable route to stabilize some compounds with moderate thermodynamical stability. [ABSTRACT FROM AUTHOR]

Published
2021
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24. Spin glass behavior in A-site ordered YBaMn2O6 compound.

Author

Gao, Qing-Qing, Li, Jing-Bo, Li, Guan-Nan, Rao, Guang-Hui, Luo, Jun, Liu, Guang-Yao, and Liang, Jing-Kui

Subjects
SPIN glasses, MAGNETIC properties, MAGNETIZATION, YTTRIUM compounds, ANTISITE defects
Abstract

Magnetic properties of the A-site ordered YBaMn2O6 compound have been investigated by dc magnetic measurements. The divergence between zero-field-cooled and field-cooled susceptibilities at about 45 K suggests the presence of a spin-glass-like behavior. Thermal remnant magnetization, isothermal remnant magnetization, and memory effect measurements reveal the time relaxation of magnetization below 45 K, confirming the spin glass feature of the YBaMn2O6 sample. Detailed x-ray diffraction analysis demonstrates the existence of local antisite disorder on the ordered A sites, which might be the origin of the spin-glass behavior in the compound. [ABSTRACT FROM AUTHOR]

Published
2013
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35. Correction: Corrigendum: Giant barocaloric effect in hexagonal Ni2In-type Mn-Co-Ge-In compounds around room temperature

Author

Wu, Rong-Rong, primary, Bao, Li-Fu, additional, Hu, Feng-Xia, additional, Wu, Hui, additional, Huang, Qing-Zhen, additional, Wang, Jing, additional, Dong, Xiao-Li, additional, Li, Guan-Nan, additional, Sun, Ji-Rong, additional, Shen, Fei-Ran, additional, Zhao, Tong-Yun, additional, Zheng, Xin-Qi, additional, Wang, Li-Chen, additional, Liu, Yao, additional, Zuo, Wen-Liang, additional, Zhao, Ying-Ying, additional, Zhang, Ming, additional, Wang, Xian-Cheng, additional, Jin, Chang-Qing, additional, Rao, Guang-Hui, additional, Han, Xiu-Feng, additional, and Shen, Bao-Gen, additional

Published
2016
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40. Giant barocaloric effect in hexagonal Ni2In-type Mn-Co-Ge-In compounds around room temperature

Author

Wu, Rong-Rong, primary, Bao, Li-Fu, additional, Hu, Feng-Xia, additional, Wu, Hui, additional, Huang, Qing-Zhen, additional, Wang, Jing, additional, Dong, Xiao-Li, additional, Li, Guan-Nan, additional, Sun, Ji-Rong, additional, Shen, Fei-Ran, additional, Zhao, Tong-Yun, additional, Zheng, Xin-Qi, additional, Wang, Li-Chen, additional, Liu, Yao, additional, Zuo, Wen-Liang, additional, Zhao, Ying-Ying, additional, Zhang, Ming, additional, Wang, Xian-Cheng, additional, Jin, Chang-Qing, additional, Rao, Guang-Hui, additional, Han, Xiu-Feng, additional, and Shen, Bao-Gen, additional

Published
2015
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41. Thermodynamic study on the Sm-Ba-Cu-O system

Author

Liang Jing-Kui, Wei Shoukun, Chen Xiao-long, Qiao Zhiyu, Rao Guang-Hui, and Xing Xianran

Subjects
Materials science, General Physics and Astronomy, Physical chemistry, Thermodynamics, Cubic zirconia, Solid state electrolyte, Standard enthalpy change of formation, EMF measurement, Decomposition, Single crystal
Abstract

The assembly for EMF measurement with CaF2 single crystal or MgO partially stabilized zirconia as solid state electrolyte has been constructed. From the EMF data, the standard Gibbs energies, standard enthalpies of formation and standard entropies of six complex oxides in the Sm-Ba-Cu-O system were calculated. The decomposition pressures of these complex oxides were derived.

Published
1996

43. Structure and magnetic properties of NdCo13−xSix

Author

Yang Fu-ming, Tang Weihua, Rao Guang-Hui, and Liang Jing-Kui

Subjects
Tetragonal crystal system, Crystallography, Magnetization, Materials science, Magnetic moment, Ferromagnetism, General Physics and Astronomy, Curie temperature, Thermomagnetic convection, Crystal structure, Powder diffraction
Abstract

NdCo13-xSix (2.5 less than or equal to x less than or equal to 4.0) compounds have been prepared by are melting and subsequent annealing. X-ray powder diffraction indicated that they crystallized in a tetragonal NaZn13-derivative structure. Thermomagnetic measurements in an applied held of 1.2 T revealed that the compounds are ferromagnetic. From the magnetization at 1.5 K a value of 2.2 mu(B) is obtained for the magnetic moment of Nd3+, and this value is about 1.4 mu(B) smaller than the value of a free Nd3+ ion, i.e., the Nd3+ moment in these compounds seems to be significantly quenched. (C) 1995 American Institute of Physics.

Published
1995

44. Phase separation in Sr doped BiMnO 3

Author

Li, Guan-Nan, primary, Rao, Guang-Hui, additional, Huang, Qing-Zhen, additional, Gao, Qing-Qing, additional, Luo, Jun, additional, Liu, Guang-Yao, additional, Li, Jing-Bo, additional, and Liang, Jing-Kui, additional

Published
2014
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46. Study on Magnetic and Corrosion Properties of Ce16Fe95-xCoxB8 (x=0-4) Alloys

Author

Fang, Chang Cheng, Yao, Qing Rong, Xu, Yong Qiang, Zhou, Huai Ying, Rao, Guang Hui, Deng, Jian Qiu, and Wang, Zhong Min

Abstract

To understand the phase composition and improve the magnetic performances of Ce2Fe14B-type alloys, the ribbons of Ce16Fe95-xCoxB8 (x=0-4.0) were prepared by melt-spinning at a quench wheel velocity of 40 m/s. The phase composition and magnetic properties of Ce16Fe95-xCoxB8 (x=0-4.0) alloys were investigated. XRD results indicated that the main phase existed in the as-spun ribbons is Ce2Fe14B. The amorphous formation ability and thermal stability of as-spun ribbons were enhanced by trace cobalt addition. Co-doped samples had higher Curie temperature compared with bare Ce2Fe14B, which signified that Co atoms could substitute for Fe directly into Ce2Fe14B phase. The corrosion potential of alloys from-1089mV (vs. SCE) to-1077mV (vs. SCE) which indicated that the Co-doped provided better corrosion protection properties for the Ce-Fe-B magnet compared with bare substrate.

Published
2018
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