High-pressure and high-temperature electrical resistivity of ferromagnetic transition metals: Nickel and iron

1986 ◽  
Vol 34 (11) ◽  
pp. 8086-8100 ◽  
Author(s):  
Mohammad Yousuf ◽  
P. Ch. Sahu ◽  
K. Govinda Rajan
2005 ◽  
Vol 59 (14-15) ◽  
pp. 1764-1766 ◽  
Author(s):  
R. Selva Vennila ◽  
N. Victor Jaya ◽  
S. Natarajan

2019 ◽  
Vol 34 (01) ◽  
pp. 2050006
Author(s):  
Lisha Xue ◽  
Chao Fang ◽  
Weixia Shen ◽  
Manjie Shen ◽  
Wenting Ji ◽  
...  

High-pressure technique is an effective route to synthesize thermoelectric materials and tune transport properties simultaneously. In this work, S-doped copper–selenium compounds [Formula: see text], [Formula: see text] were successfully synthesized by high-pressure and high-temperature (HPHT) technology in just 30 min. [Formula: see text] samples show layered morphology composed of abundant pores and lattice defects. The appropriate S introduction ([Formula: see text] and 0.03) can effectively enhance Seebeck coefficient and reduce the thermal conductivity of [Formula: see text]. Compared with the pure [Formula: see text] sample, [Formula: see text] exhibits a 30% lower thermal conductivity, but the decline of power factor by the distinctly increased electrical resistivity at high temperature results in a smaller zT at temperature [Formula: see text] K. The variations of thermoelectric properties are resulted from the competitive effects between S-doping and actual composition change (Cu:S). It indicates that S-doping is not so effective in improving the zT value of [Formula: see text] materials by high-pressure synthesis.


Materials ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1212 ◽  
Author(s):  
Changchun Wang ◽  
Lele Song ◽  
Yupeng Xie

Single-phase tungsten diboride (WB2) was synthesized at high pressure and high temperature. The different grain sizes ranging from 300 nm to 3 µm were successfully obtained in WB2 by controlling the experimental conditions. The effects of grain size on hardness and resistivity properties were investigated. The Vickers hardness of WB2 was modulated with grain size. The maximum asymptotic Vickers hardness is 25.5 GPa for WB2 with a grain size of 300 nm which is a 10% increase compared to WB2 with a grain size of 3 µm. The optimal electrical resistivity of WB2 was 10−7 Ωm with the biggest grain size of 3 µm, which is ascribed to low grain boundary density. The superior properties of hardness and electrical resistivity demonstrate that WB2 should be a new functional hard material replacing WC which is widely used in industrial production.


Pramana ◽  
1985 ◽  
Vol 24 (6) ◽  
pp. 825-835 ◽  
Author(s):  
Mohammad Yousuf ◽  
P Ch Sahu ◽  
K Govinda Rajan

2021 ◽  
Author(s):  
Simon David Kloß ◽  
Paul Attfield

Calcium nitridonickelate(II) Ca2NiN2 has been prepared through a high-temperature and high-pressure azide-mediated redox reaction, demonstrating that this method can stabilise nitrides of late transition metals in relatively high oxidation states....


2010 ◽  
Vol 107 (3) ◽  
pp. 033708 ◽  
Author(s):  
Yang Wang ◽  
Yu Sui ◽  
Xianjie Wang ◽  
Wenhui Su ◽  
Xiaoyang Liu

2013 ◽  
Vol 209 ◽  
pp. 48-51
Author(s):  
Priyank Kumar ◽  
Nisarg K. Bhatt ◽  
Pulastya R. Vyas ◽  
Asvin R. Jani ◽  
Vinod B. Gohel

Volume thermal expansion of some fcc transition metals have been studied using improved lattice dynamical model. In this approach, the contribution of s like electron is calculated in 2nd order perturbation theory for the local model pseudopotential (Heine - Abrenkov) while that of the d electrons is taken into account by introduction of repulsive potential. The present study confirms that the use of improved model to study such anharmonic property yields satisfactory results. Looking to the success of present study, the present lattice mechanical model may be used to study thermophysical properties in high temperature and high pressure regions.


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