A synergic effect of sodium on the phase transition of tungsten-doped vanadium dioxide

2014 ◽  
Vol 16 (19) ◽  
pp. 8783-8786 ◽  
Author(s):  
Qiang Song ◽  
Weitao Gong ◽  
Guiling Ning ◽  
Hassan Mehdi ◽  
Guiqi Zhang ◽  
...  

A synergic effect of sodium on the metal–insulator transition temperature reduction of tungsten-doped vanadium dioxide is noted.

2015 ◽  
Vol 17 (17) ◽  
pp. 11638-11646 ◽  
Author(s):  
Xinfeng He ◽  
Yijie Zeng ◽  
Xiaofeng Xu ◽  
Congcong Gu ◽  
Fei Chen ◽  
...  

Using ultraviolet-infrared spectroscopy and first principles calculations, it is revealed that changes in the orbital structure can regulate the W-doped VO2 phase transition temperature.


AIP Advances ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 035120
Author(s):  
Kazuma Tamura ◽  
Teruo Kanki ◽  
Shun Shirai ◽  
Hidekazu Tanaka ◽  
Yoshio Teki ◽  
...  

The present work studies the microstructural and electrical properties of La0.9Pb0.1MnO3 and La0.8Y0.1Pb0.1MnO3 ceramics synthesized by solid-state route method. Microstructure and elemental analysis of both samples were carried out by field emission scanning electron microscope (FESEM) and energy dispersive spectroscopy (EDS) method, respectively. Phase analysis by X-ray diffraction (XRD) indicated formation of single phase distorted structure. The XRD data were further analyzed by Rietveld refinement technique. Raman analysis reveals that Y atom substitutes La site into the LPMO with shifting of phonon modes. The temperature variation of resistivity of undoped and Y-doped La0.9Pb0.1MnO3 samples have been investigated. The electrical resistivity as a function of temperature showed that all samples undergo an metal-insulator (M-I) transition having a peak at transition temperature TMI. Y-doping increases the resistivity and the metal-insulator transition temperature (TMI) shifts to lower temperature. The temperature-dependent resistivity for temperatures less than metal-insulator transition is explained in terms the quadratic temperature dependence and for T > TMI, thermally activated conduction (TAC) is appropriate. Variation of frequency dispersion in permittivity and loss pattern due to La-site substitution in LPMO was observed in the dielectric response curve.


2021 ◽  
Vol 317 ◽  
pp. 17-21
Author(s):  
Muhammad Syazwan Mohd Sabri ◽  
Nur Ain Athirah Che Apandi ◽  
Norazila Ibrahim

The electroresistance, ER effect of La0.85Ag0.15Mn1-xMoxO3 (x = 0.00 and 0.05) samples prepared using solid method are investigated. The increased of applied current from 5 mA to 10 mA does not change the metal-insulator transition temperature, TMI for both samples however decreased the resistivity in the temperature region of 50 K – 300 K. Both samples exhibit large ER effect at low temperature region. At TMI, the ER value is 75.5% (x =0) and decrease to 34.15% (x = 0.05). However, at 300 K, the value of ER increases to 57 % for Mo substituted sample, and the value decreases to 6.4% for the x =0 sample. The enhanced ER effect at 300 K may be due to the growth of conductive filaments under increased applied current. The increase of applied current may perturb the arrangement of magnetic inhomogeneity induced by Mo substitution, result in reduction of resistivity and lead to the observation of ER effect. These findings suggest potential application of La0.85Ag0.15Mn1-xMoxO3 (x = 0.05) in spintronic devices.


2019 ◽  
Vol 55 (1) ◽  
pp. 99-106
Author(s):  
Xiaofen Guan ◽  
Rongrong Ma ◽  
Guowei Zhou ◽  
Zhiyong Quan ◽  
G. A. Gehring ◽  
...  

2020 ◽  
Vol 22 (24) ◽  
pp. 13474-13478
Author(s):  
Haichang Lu ◽  
Stewart Clark ◽  
Yuzheng Guo ◽  
John Robertson

We show that a non-collinear spin density GGA+U functional calculation can describe the enthalpy difference (latent heat) of ΔE0 = −44.2 meV per formula unit, similar to the experimental value, between the paramagnetic rutile and the M1 phases of VO2.


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