The Competitive and Combining Effects of Grain Boundary and Fe/Mo Antisite Defects on the Low-Field Magnetoresistance in Sr2 FeMoO6

2013 ◽  
Vol 97 (4) ◽  
pp. 1137-1142 ◽  
Author(s):  
Jin-Feng Wang ◽  
Zheng Li ◽  
Xi-Jun Xu ◽  
Zheng-Bin Gu ◽  
Guo-Liang Yuan ◽  
...  
Keyword(s):  
Grain Boundary ◽  
Low Field ◽  
Antisite Defects

Dependence on film thickness of grain boundary low-field magnetoresistance in thin films of La0.7Ca0.3MnO3

2001 ◽  
Vol 89 (11) ◽  
pp. 6970-6972 ◽  
Author(s):  
N. K. Todd ◽  
N. D. Mathur ◽  
M. G. Blamire
Keyword(s):  
Thin Films ◽  
Grain Boundary ◽  
Film Thickness ◽  
Low Field

Enhancement of the low field magnetoresistance by grain boundary modification in Sr2FeMoO6+δ

2002 ◽  
Vol 320 (1-4) ◽  
pp. 107-110 ◽  
Author(s):  
D Niebieskikwiat ◽  
A Caneiro ◽  
R.D Sánchez ◽  
J Fontcuberta
Keyword(s):  
Grain Boundary ◽  
Low Field ◽  
Boundary Modification

scholarly journals Atomistic Studies of Grain Boundaries in NiAl

1994 ◽  
Vol 364 ◽  
Author(s):  
M. Yan ◽  
S. P. Chen ◽  
V. Vitek
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Cohesive Strength ◽  
Antisite Defects

AbstractThis paper presents the results of atomistic studies of grain boundaries in NiAl B2 alloy. The interatomic forces are described by Finnis-Sinclair type N-body potentials, and are fitted to properties of NiAl. The results show that the structure, energy and cohesive strength of a grain boundary depend strongly on its chemistry, and a grain boundary possessing more Al is the weakest. Energies of antisite defects at the grain boundary ∑5 {210} are also calculated, and the results suggest that Al has much larger tendency to segregate at a grain boundary than Ni does.

Grain-boundary room-temperature low-field magnetoresistance in Sr2FeMoO6 films

2000 ◽  
Vol 87 (9) ◽  
pp. 6761-6763 ◽  
Author(s):  
H. Q. Yin ◽  
J.-S. Zhou ◽  
R. Dass ◽  
J.-P. Zhou ◽  
J. T. McDevitt ◽  
...  
Keyword(s):  
Grain Boundary ◽  
Room Temperature ◽  
Low Field

scholarly journals Effects of Organic Material on Magnetoresistance in Electron-doped Double Perovskite

2021 ◽  
Author(s):  
Ya Fang Li ◽  
Yu Liu ◽  
Yan-Ming Zhang ◽  
Jin-Feng Wang
Keyword(s):  
Oleic Acid ◽  
Grain Boundary ◽  
Small Molecules ◽  
Room Temperature ◽  
Double Perovskite ◽  
Double Perovskites ◽  
Low Field ◽  
Band Filling ◽  
High Spin Polarization ◽  
Magnetoresistance Property

Abstract The Curie temperature of electron-doped Sr2FeMoO6 can be optimized significantly due to the band-filling effect, but accompanying an almost absent low-field magnetoresistance (LFMR), which is unfavorable to applications in the magnetoresistive devices operated at room-temperature. Our previous works confirmed that, a remarkable enhanced LFMR was observed in Sr2FeMoO6 by modifying the grain boundary with insulating organic small molecules (glycerin, CH2OHCHOHCH2OH). However, in this work, modifying the grain boundary strength of the La0.5Sr1.5FeMoO6 with the insulating organic macromolecules (oleic acid, CH3(CH2)7CH=CH(CH2)7COOH) or small molecules (glycerin), both of them have negligible functions on the magnetoresistance behavior in La0.5Sr1.5FeMoO6. Contrary to the glycerin-modified Sr2FeMoO6, Sr2FeMoO6/oleic acid composites don’t exhibit an obviously increased magnetoresistance property. Based on the above experimental results and the related works, it is proposed that, maintaining high spin polarization of the carriers at the Fermi level and improving the tunneling process across the grain boundary by using the suitable organic materials are decisive factors for optimizing the magnetoresistance behavior in the similar electron-doped double perovskites.

Structure of the Σ=5 (310) interface in NiAl

1993 ◽  
Vol 51 ◽  
pp. 984-985
Author(s):  
Richard W. Fonda ◽  
David E. Luzzi
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Point Defects ◽  
Low Temperatures ◽  
High Resolution Electron Microscopy ◽  
Image Simulation ◽  
Embedded Atom ◽  
Resolution Electron ◽  
Antisite Defects ◽  
Simulated Images

The atomic structure of the Σ=5 [001] (310) grain boundary in NiAl was examined by high resolution electron microscopy and multislice image simulation. As in most other intermetallic compounds, the grain boundaries in NiAl are intrinsically brittle at low temperatures. Although there have been few studies on this alloy, the energies of NiAl grain boundaries have been calculated using embedded atom potentials for both stoichiometric and non-stoichiometric structures. These studies are consistent with the results of Bradley and Taylor, which indicate that nickel-rich compositions result from nickel antisite defects on the aluminum sublattice, while aluminum-rich compositions produce constitutional vacancies on the nickel sublattice, and with recent field ion microscopy results on nickel-rich alloys.The Σ=5 grain boundary was prepared by diffusion bonding at 1000 °C. A JEOL 4000EX was used for HREM imaging and the NUMIS multislice simulation program was used to simulated images. Analysis of these images considered the effects of grain boundary expansion, rigid body displacements along the boundary, grain boundary stoichiometry, and point defects at the boundary.

In-Plane Grain Boundary Effects on the Transport Properties of La0.7Sr0.3MnO3-δ Thin Films

1997 ◽  
Vol 494 ◽  
Author(s):  
J. Y. Gu ◽  
S. B. Ogale ◽  
K. Ghosh ◽  
T. Venkatesan ◽  
R. Ramesh ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Boundary Effects ◽  
Epitaxial Relationship ◽  
X Ray ◽  
Low Field ◽  
Grain Structures ◽  
Transmission Electron

ABSTRACTC-axis oriented La0.7Sr0.3MnO3.δ (LSMO) films were fabricated on the top of SrTiO3/YBa2Cu3O7 grown on MgO(001) substrates. From x-ray φ-scan and planar transmission electron microscopy measurements, the LSMO layer in the LSMO/SrTiO3/YBa2Cu3O7/MgO heterostructure is found to have coherent in-plane grain boundaries with a predominance of 45° rotations (between [100] and [110] grains) in addition to the cube-on-cube epitaxial relationship. Also, epitaxial LSMO/Bi4Ti3O12/LaAl03 (001) and c-axis textured LSMO/Bi4Ti3O12/SiO2/Si(001) with random in-plane grain boundaries are introduced as the counterparts for comparison. The resistivity and magnetoresistance (MR) of LSMO layer were measured and compared in these three different heterostructures. The low field MR at low temperature shows a dramatic dependence on the nature of the grain boundary. An attempt is made to interpret these results on the basis of correlation between the magnetic properties and grain structures.

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