STUDY OF STRUCTURAL, ELECTRICAL TRANSPORT AND MAGNETIC PROPERTIES IN La1-xAgxMnO3 COMPOUNDS

2004 ◽  
Vol 18 (05n06) ◽  
pp. 221-231 ◽  
Author(s):  
MANORANJAN KAR ◽  
S. RAVI
Keyword(s):  
Magnetic Field ◽  
Electrical Transport ◽  
Single Phase ◽  
Ac Susceptibility ◽  
X Ray Diffraction ◽  
Metal Insulator Transition ◽  
Metal Insulator ◽  
Phase Form ◽  
X Ray ◽  
Maximum Value

X-ray diffraction, electrical resistivity and ac susceptibility measurements have been carried out on La 1-x Ag x MnO 3 compounds for x=0.05 to 0.30. These samples are found to be in single phase form with [Formula: see text] space group and with typical lattice parameters a=b=5.524Å and c=13.349Å for x=0.05 sample. The Mn–O–Mn bond angles and variance, σ2 are found to increase with doping. Metal-insulator transitions in the temperature range 254 to 259 K have been observed. These materials exhibit paramagnetic to ferromagnetic transitions in the vicinity of metal-insulator transition temperatures. The paramagnetic susceptibility could be analyzed using Curie–Weiss law. All the above samples exhibit colossal magneto-resistivity and its maximum value is found to be 73% for x=0.15 sample at 50 kOe magnetic field.

STRUCTURE, ELECTRICAL TRANSPORT AND MAGNETO-RESISTANCE PROPERTIES OFLa5/8Ca3/8MnO3MANGANITE SYNTHESIZED WITH DIFFERENT MANGANESE PRECURSORS

2012 ◽  
Vol 26 (06) ◽  
pp. 1150039 ◽  
Author(s):  
M. NAVASERY ◽  
S. A. HALIM ◽  
K. P. LIM ◽  
S. K. CHEN ◽  
A. S. ROSLAN ◽  
...  
Keyword(s):  
Electrical Transport ◽  
Single Phase ◽  
Xrd Analysis ◽  
Solid State Reaction Method ◽  
Route Selection ◽  
Orthorhombic Structure ◽  
X Ray Diffraction ◽  
Metal Insulator ◽  
X Ray ◽  
Magneto Resistance

We synthesized the polycrystalline manganite of La5/8Ca3/8MnO3with three different manganese routes prepared through a solid state reaction method. The effects of the manganese route selection on the structure, electrical transport and magneto-transport properties were examined in this study. The samples were characterized using X-ray diffraction (XRD) and SEM to identify their structure and morphology. XRD analysis confirmed that all samples were in single phase with orthorhombic structure and belonged to the Pnma space group. The average grain sized samples with manganese route of Mn2O3and MnCO3had a grain size of 1.2–8.7 μm and 2–7.5 μm, respectively. For the MnO2route, the sample had a small melt-like shape with higher porosity. The metal–insulator transition temperature, TMI, for LCMO ( Mn2O3), LCMO ( MnO2) and LCMO ( MnCO3) samples were 270 K, 266 K and 258 K, respectively. All the samples showed negative magneto-resistance with significant increase in value near the TMItemperature. The highest CMR (colossal magneto-resistance) ratio was found in LCMO ( Mn2O3), -22.06% at 270 K, followed by -16.69% for LCMO ( MnO2) at 80 K, and 15.2% for LCMO ( MnCO3) at 100 K in a 1 T magnetic field.

Structural, Magnetic and Magneto-tranport Properties of Reactive-sputtered Fe3O4 Thin Films

2010 ◽  
Vol 1250 ◽  
Author(s):  
Xinghua Wang ◽  
Sarjoosing Goolaup ◽  
Peng Ren ◽  
Wen Siang Lew
Keyword(s):  
Thin Films ◽  
Photoelectron Spectroscopy ◽  
Single Phase ◽  
Native Oxide ◽  
X Ray Diffraction ◽  
Verwey Transition ◽  
Electrical Measurements ◽  
Metal Insulator ◽  
X Ray ◽  
Sample Measurement

AbstractThin films of magnetite (Fe3O4) are grown on a single-crystal Si/SiO2 (100) substrate with native oxide using DC reactive sputtering technique at room tempreture (RT) and 300C. The x-ray diffraction(XRD) result shows the thermal energy during deposition enhances the crystallization of the Fe3O4 and x-ray photoelectron spectroscopy confirms the film deposited at 300C is single-phase Fe3O4 while the film deposited at RT is mostly ν-Fe2O3. The electrical measurements show that the resistivity of the Fe3O4 film increases exponentially with decreasing temperature, and exhibit a sharp metal-insulator transition at around 100 K, indicating the Verwey transition feature. The saturation magnetization Ms of Fe3O4 film measured by vibrating sample measurement (VSM) at RT was found to be 445 emu/cm3.

Thermoelectric properties and microstructure of large-grain Mg2Sn doped with Ag

2009 ◽  
Vol 1166 ◽  
Author(s):  
Haiyan Chen ◽  
Nick Savvides
Keyword(s):  
Electron Microscopy ◽  
Electrical Conductivity ◽  
Single Phase ◽  
Silver Content ◽  
X Ray Diffraction ◽  
Thermoelectric Power Factor ◽  
X Ray ◽  
Maximum Value ◽  
Vertical Bridgman ◽  
Scanning Electron

AbstractMg2Sn ingots, doped p-type by the addition of 0–1.0 at. % Ag, were prepared by the vertical Bridgman method at growth rates ∼0.1 mm/min. The crystalline quality and microstructure of ingots were analyzed by X-ray diffraction, scanning electron microscopy and energy-dispersive X-ray spectroscopy. The single-phase Mg2Sn ingots consist of highly oriented large grains. Measurements of the Hall coefficient, Seebeck coefficient α, and electrical conductivity σ in the temperature range 80–700 K were conducted to study the dependence on the silver content, and to determine the thermoelectric power factor α2σ which reached a maximum value 2.4×10-3 W m-1 K-2 at 410 K for 1.0 at.% Ag content.

scholarly journals Electrical Transport Properties and Magnetoresistance of Pr0.67Sr0.33MnO3-NiO Composites

2017 ◽  
Vol 268 ◽  
pp. 292-296
Author(s):  
Kean Pah Lim ◽  
Abdul Halim Shaari ◽  
Soo Kien Chen ◽  
Hassan Jumiah ◽  
Siau Wei Ng ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Crystal Structure ◽  
Solid State ◽  
Electrical Transport ◽  
Magnetic Field Dependence ◽  
Single Phase ◽  
Parent Compound ◽  
Secondary Phase ◽  
Electrical Transport Properties ◽  
X Ray

A series of polycrystalline bulk samples (Pr0.67Sr0.33MnO3)1-x/ (NiO)x were prepared by solid state reaction, and its structure, electrical transport and magnetoresistance properties were investigated. X-ray analysis showed that parent compound of Pr0.67Sr0.33MnO3 (PSMO) formed in single phase with crystal structure of orthorhombic while secondary phase of NiO can be detected with the addition of composite. The electrical properties showed that the resistivity increased with the addition of NiO due to enhancement of spin dependent-tunneling scattering across the artificial grain boundaries of NiO layer. Magnetic field dependence MR curve at various temperatures clearly indicates that extrinsic magnetoresistance had been enhanced due to addition of NiO as the artificial grain boundary.

Sign in / Sign up

Export Citation Format

Share Document