Thermal Transport Properties of Ca3Co4O9 with Mg Substitution

Polycrystalline Ca3-xMgxCo4O9（x=0-0.3）ceramics were prepared by the sol–gel method combined with the ordinary pressing sintering and the thermal conductivities were measured from room temperature to 673 K. The influence of Mg2+ substitution for Ca2+ on the thermal conductivities of Ca3Co4O9 ceramics was investigated systematically. The influence of Mg doping on the thermal conductivities is mainly embodied in the lattice thermal conductivities, which shows a significant decrease with the increase of the dopant content for the samples with x ≤ 0.2, while the carrier thermal conductivity had no obvious change with Mg doping increasing. These results indicated that the thermal conductivities of the material could be reduced remarkably with the substitution of Mg from 1.427 W/m·K to 0.731 W/m·K at 573 K with x = 0.2.

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Effects of Mg Substitution on the Thermoelectric Properties of Ca3Co4O9-Based Materials

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.84-85.671 ◽

2011 ◽

Vol 84-85 ◽

pp. 671-675 ◽

Cited By ~ 1

Author(s):

Xiao Ling Qi ◽

You Yu Fan ◽

Ling Ke Zeng ◽

Dong Sheng Zhu

Keyword(s):

Thermal Conductivity ◽

Thermoelectric Properties ◽

Figure Of Merit ◽

Room Temperature ◽

Lattice Thermal Conductivity ◽

Sol Gel ◽

Dopant Content ◽

Mg Doping ◽

Mg Content ◽

Mg Substitution

Polycrystalline Ca3-xMgxCo4O9(x=0-0.3)ceramics were prepared by the sol–gel method combined with the ordinary pressing sintering and the thermoelectric properties were measured from room temperature to 673 K. The substitution of Mg2+for Ca2+had a greater impact on the thermoelectric properties of Ca3Co4O9. The electrical conductivity and the thermal conductivity reduced significantly with increasing Mg content, and the Seebeck coefficient increased simultaneously. The influence of Mg doping on the thermal conductivity is mainly embodied in the lattice thermal conductivity of Ca3Co4O9. The lattice thermal conductivity showed a significant change with the increase of the dopant content, while the carrier thermal conductivity had no obvious change with the doping increasing. These results indicated that the thermoelectric properties of the material could be optimized remarkably with the substitution of Mg. The figure of meritZreached 1.08×10-4K-1at 573 K for the sample of Ca2.8Mg0.2Co4O9.

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Magnetic and Electrical Transport Properties of Double Perovskite Sr2FeMoO6Prepared by Sol-Gel Method

E-Journal of Chemistry ◽

10.1155/2011/984862 ◽

2011 ◽

Vol 8 (s1) ◽

pp. S189-S194 ◽

Cited By ~ 5

Author(s):

Yong-Qing Zhai ◽

Jing Qiao ◽

Zhang Zhang

Keyword(s):

Transport Properties ◽

Electrical Transport ◽

Room Temperature ◽

Sol Gel ◽

Double Perovskite ◽

Reducing Agent ◽

Perovskite Oxide ◽

Electrical Transport Properties ◽

Gel Method ◽

Sol Gel Method

With activated carbon for reducing agent, the sol-gel method was used to prepare the giant magnetoresistance materials Sr2FeMoO6, which is the double Perovskite oxide. The structure, morphology, magnetic and electrical transport properties were investigated respectively by x-ray diffraction, scanning electron microscopy and vibrating sample magnetometer. The as-synthesized sample is Sr2FeMoO6with tetragonal crystal structure and I4/mmm space group and unit cell parameter is a = 5.580Å, c = 7.882Å. The primary particles are spherical in shape and the grain size is below 100 nm. The curie temperature is above room temperature and the saturation magnetization is 13.321 A·m2/kg under 1.0 T at room temperature. The sample exhibit typical semiconductor behavior and the conductive mechanism can be described by small polaron variable range hopping model. The room temperature magnetoresistance of the sample under 1.0 T field is up to -10.02%. Moreover, it is found the dosage of citric acid and the amount of reducing agent has great effect on the phase structure and magnetic properties of the samples.

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Vacuum Annealing Induced Room-Temperature Ferromagnetism in Co 0.1 Ti 0.9 O 2−δ Films Prepared by Sol-Gel Method

Chinese Physics Letters ◽

10.1088/0256-307x/25/7/084 ◽

2008 ◽

Vol 25 (7) ◽

pp. 2638-2641

Author(s):

Liu Li-Feng ◽

Kang Jin-Feng ◽

Wang Yi ◽

Zhang Xing ◽

Han Ru-Qi

Keyword(s):

Room Temperature ◽

Vacuum Annealing ◽

Room Temperature Ferromagnetism ◽

Sol Gel ◽

Gel Method ◽

Sol Gel Method

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Impedance Spectroscopy Study of LiTaO3 Powder Synthesized via Sol-Gel Method

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.545.275 ◽

2012 ◽

Vol 545 ◽

pp. 275-278 ◽

Cited By ~ 1

Author(s):

Lili Widarti Zainuddin ◽

Norlida Kamarulzaman

Keyword(s):

Room Temperature ◽

Single Phase ◽

Sol Gel ◽

Rhombohedral Structure ◽

Spectroscopy Study ◽

X Ray Diffraction ◽

Gel Method ◽

X Ray ◽

Sol Gel Method ◽

Impedance Spectroscopy Study

A ceramics sample of LiTaO3 was prepared using a sol-gel method. The sample is annealed at 750 °C for 48 hours. X-ray diffraction analysis indicate the formation of single phase, rhombohedral structure. An ac impedance study was used to analyse the conductivity of LiTaO3 at room temperature and at various temperatures.

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The influence of Mg doping on the dielectric and tunable properties of (Ba0.6Sr0.4)0.925K0.075TiO3 thin films fabricated by sol–gel method

Journal of Crystal Growth ◽

10.1016/j.jcrysgro.2005.12.111 ◽

2006 ◽

Vol 290 (1) ◽

pp. 121-126 ◽

Cited By ~ 12

Author(s):

Xiaohua Sun ◽

Shishang Guo ◽

Gengzhu Wu ◽

Meiya Li ◽

Xing-Zhong Zhao

Keyword(s):

Thin Films ◽

Sol Gel ◽

Gel Method ◽

Sol Gel Method ◽

Mg Doping ◽

Tunable Properties

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Pyroelectric Properties of the Plt(10) Thin Film on the P-Doped Poly Silicon

MRS Proceedings ◽

10.1557/proc-433-413 ◽

1996 ◽

Vol 433 ◽

Author(s):

Seong Jun Kang ◽

Yung Sup Yoon ◽

Dong Il Kim

Keyword(s):

Thin Film ◽

Dielectric Constant ◽

Curie Temperature ◽

Room Temperature ◽

Sol Gel ◽

Pyroelectric Coefficient ◽

Pyroelectric Properties ◽

Gel Method ◽

Sol Gel Method ◽

Poly Silicon

AbstractWe have studied the pyroelectric properties of the PLT(10) thin film deposited on a p-doped poly-Si electrode by using the sol-gel method. Measurement of the dielectric constant as a function of temperature shows the typical characteristics of a ferroelectric. The dielectric constant reaches a maximum at 295°C, which can be thought of as the Curie temperature. The PLT(10) thin film on p-doped poly-Si fabricated in this research shows excellent pyroelectric properties. The pyroelectric coefficient and the fiqures of merit, Fv and FD at room temperature are measured as 5.76 × 10−8 C/cm2 °C, 1.17 × 10−10C-cm/J and 0.93 × 10−8C-cm/J, respectively.

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