STUDIES OF TRANSPORT PROPERTIES OF RFe1-xNixO3 (x ≤ 0.5) WHERE R = Nd, Sm AND Gd

2011 ◽  
Vol 25 (21) ◽  
pp. 1787-1794 ◽  
Author(s):  
ABIDA BASHIR ◽  
MOHD IKRAM ◽  
RAVI KUMAR

We present here the electrical transport properties of RFe 1-x Ni x O 3 (x ≤ 0.5) where R = Nd , Sm and Gd and the correlation between these systems. The resistivity increases as the rare ion is changed from Nd to Sm . The resistivity increases from the magnitude of the order of 103 to 106 Ωcm at lower temperatures and from 10 to 105 Ωcm as the temperature is increased. Also, the resistivity decreases as the concentration of Ni is increased within the ensemble showing a semiconducting behavior. The resistivity data is fitted with the Greaves Variable Range Hopping model which fits in the intermediate range of temperatures. There is decrease in gap parameter, increase in conductivity and increase in the density of states at Fermi level which clarify that the correlation length in the conducting network increases with the increase in Ni substitution. The Debye temperature decreases as the Ni concentration increases and follows the same trend as the rare earth ion is replaced.

2017 ◽  
Vol 31 (17) ◽  
pp. 1750195
Author(s):  
Li Zhang ◽  
Yibao Li ◽  
Zhen Tang ◽  
Yan Deng ◽  
Hui Yuan ◽  
...  

Microstructures, electrical transport and magnetic properties of Sr[Formula: see text]Ti[Formula: see text]Co[Formula: see text]O[Formula: see text] ceramics are investigated. With Co doping, the Sr[Formula: see text]Ti[Formula: see text]Co[Formula: see text]O[Formula: see text] ceramics remain tetragonal structure while the grain size is decreased with doping. Magnetic moment is enhanced with Co doping and ferromagnetism is observed at low temperatures for Co-doped Sr[Formula: see text]TiO[Formula: see text]. The Sr[Formula: see text]Ti[Formula: see text]Co[Formula: see text]O[Formula: see text] and Sr[Formula: see text]Ti[Formula: see text]Co[Formula: see text]O[Formula: see text] show semiconductor-like transport properties, which can be well fitted by Mott variable range hopping model. The results will provide an effective route to synthesize Sr[Formula: see text]Ti[Formula: see text]Co[Formula: see text]O[Formula: see text] ceramics as well as to investigate the physical properties.


2001 ◽  
Vol 16 (3) ◽  
pp. 774-777 ◽  
Author(s):  
Yong-Chae Chung ◽  
Han-Ill Yoo

Electrical transport properties, electrical conductivity, and thermoelectric power of a single-crystalline Mn0.45Zn0.43Fe2.12O4 were measured as functions of temperature in the range of 25 to 1000 °C. According to the small polaron hopping model, the values of the activation energy for small polaron hopping (EH) were obtained from the conductivity data in three different temperature regions: 0.032 eV for T < TC, 0.12 eV for TC < T < 600 °C, and 0.25 eV for 600 °C < T < 1000 °C. The behavior of conductivity and thermoelectric power data above TC is discussed in connection with cation redistribution.


2021 ◽  
Author(s):  
Dongha Shin ◽  
Hwa Rang Kim ◽  
Byung Hee Hong

Since of its first discovery, graphene has attracted much attention because of the unique electrical transport properties that can be applied to high-performance field-effect transistor (FET). However, mounting chemical functionalities...


Crystals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 746
Author(s):  
Meiling Hong ◽  
Lidong Dai ◽  
Haiying Hu ◽  
Xinyu Zhang

A series of investigations on the structural, vibrational, and electrical transport characterizations for Ga2Se3 were conducted up to 40.2 GPa under different hydrostatic environments by virtue of Raman scattering, electrical conductivity, high-resolution transmission electron microscopy, and atomic force microscopy. Upon compression, Ga2Se3 underwent a phase transformation from the zinc-blende to NaCl-type structure at 10.6 GPa under non-hydrostatic conditions, which was manifested by the disappearance of an A mode and the noticeable discontinuities in the pressure-dependent Raman full width at half maximum (FWHMs) and electrical conductivity. Further increasing the pressure to 18.8 GPa, the semiconductor-to-metal phase transition occurred in Ga2Se3, which was evidenced by the high-pressure variable-temperature electrical conductivity measurements. However, the higher structural transition pressure point of 13.2 GPa was detected for Ga2Se3 under hydrostatic conditions, which was possibly related to the protective influence of the pressure medium. Upon decompression, the phase transformation and metallization were found to be reversible but existed in the large pressure hysteresis effect under different hydrostatic environments. Systematic research on the high-pressure structural and electrical transport properties for Ga2Se3 would be helpful to further explore the crystal structure evolution and electrical transport properties for other A2B3-type compounds.


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