scholarly journals Spin-dependent and spin-independent channels of electrical transport in perovskite manganites

RSC Advances ◽  
2018 ◽  
Vol 8 (8) ◽  
pp. 4417-4425 ◽  
Author(s):  
J. J. Qian ◽  
W. H. Qi ◽  
Z. Z. Li ◽  
L. Ma ◽  
G. D. Tang ◽  
...  
Keyword(s):  
Electrical Transport ◽  
Current Carrier ◽  
Perovskite Manganites

A model with two channels of electrical transport (TCET) for perovskite manganites is proposed, and it is described by an equivalent device with two current-carrier channels.

Structural, Electrical Transport and Magnetoresistive Studies of Pr and Nd Substituted on La2/3Ba1/3MnO3 Perovskite

Volume 1 ◽  
2004 ◽  
Author(s):  
A. Huda ◽  
S. A. Halim ◽  
K. P. Lim ◽  
K. K. Kabashi ◽  
S. Elias ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Electrical Transport ◽  
Colossal Magnetoresistance ◽  
Resistivity Measurement ◽  
Random Access ◽  
Perovskite Manganites ◽  
Write Heads ◽  
Read Head ◽  
Lower Temperature ◽  
Xrd Patterns

Colossal magnetoresistance (CMR), as the name implies, is the phenomenon of dramatic changes in resistance attendant upon application of a magnetic field. The typical CMR material is derived from perovskite manganites with the chemical formula Ln1−xAxMnO3, where Ln is the rare earth (Ln = La, Pr, Nd, Sm) and A is the divalent metal (A = Ca, Ba, Sr). The objective of this paper is to study the effects of the doping Nd and Pr at La site on La-Ba-Mn-O ceramics using solid state reaction. The characteristics and magnetotransport properties of CMR materials are investigated. Polycrystalline (La1−xPrx)0.67Ba0.33MnO3 (x = 0, 1/6, 1/3, 1/2, 2/3, 5/6, 1) and (La1−xPrx)0.67Ba0.33MnO3 (x = 0, 1/6, 1/3, 1/2, 2/3, 5/6, 1), are doped with Pr and Nd site based manganites, calcined at 900°C for 12 hours, pelletized and sintered at 1300°C for 24 hours have been synthesized and investigated. The magnetoresistance (MR) effects are measured using the four point probe technique. The magnetoresistance defined as MR% = (Ro−RH)/RH × 100 was measured at a magnetic field of H ≤ 1T at room temperature. The MR values were increased from 7.9–12.7% and from 7.9–12.3% for doping with Nd (x = 0.17) and Pr (x = 0.33) respectively. The electrical property, Tp was determined by using standard four-point probe resistivity measurement in a temperature range of 20 K to 300 K. The result shows that Pr and Nd dopants shift the value of TP to a lower temperature. In this paper the structural pattern and microstructure property of bulk samples have been investigated via XRD, AFM and SEM. XRD patterns show that these systems are in single-phase with orthorhombic distorted perovskite structures. The rms roughness for the AFM images has obtained for undoped and doped samples. SEM micrographs have shown that undoped samples are observed to be more compact than the doped samples doped due to the existence of pores. The potential of this research is to produce magnetoresistive read head such as read/write heads in computer disc-drives, position sensor, magnetoresistive random access memory (MRAM), biomagnetic sensor and magnetic accelerometers.

scholarly journals Magnetic and electrical transport properties of perovskite manganites Pr0.6Sr0.4MxMn1-xO3 (M = Fe, Co, Ni)

AIP Advances ◽  
2017 ◽  
Vol 7 (12) ◽  
pp. 125002 ◽  
Author(s):  
X. S. Ge ◽  
Z. Z. Li ◽  
W. H. Qi ◽  
D. H. Ji ◽  
G. D. Tang ◽  
...  
Keyword(s):  
Transport Properties ◽  
Electrical Transport ◽  
Perovskite Manganites ◽  
Electrical Transport Properties

UNUSUAL MAGNETIC HYSTERESIS AND ELECTRICAL TRANSPORT BEHAVIOR IN La0.67Ca0.33MnO3/xCuO COMPOSITE

2009 ◽  
Vol 23 (26) ◽  
pp. 3107-3113 ◽  
Author(s):  
J. H. MIAO ◽  
S. L. YUAN
Keyword(s):  
Temperature Region ◽  
Electrical Transport ◽  
Magnetic Hysteresis ◽  
Phase Segregation ◽  
Percolation Model ◽  
Perovskite Manganites ◽  
Magnetoresistance Effect ◽  
Spin Glass Behavior ◽  
Glass Behavior ◽  
Warming Process

Temperature dependence of magnetization for the composite La 0.67 Ca 0.33 MnO 3 ( LCMO )/x CuO (x = 20%) has been measured in the cooling and warming process under magnetic fields of 0.5 T and 5.0 T. Unusual magnetic hysteresis behavior was observed, which is different from the spin glass behavior usually observed in perovskite manganites. It is interesting to note that in the same temperature region, the sample shows substantial magnetoresistance effect, and a relaxation behavior of resistivity has also been observed. Moreover, the ρ–T curve for the sample fits well to the phenomenological percolation model based on phase segregation. This result confirms the coexistence of ferromagnetic clusters and paramagnetic regions near T c .

Intrinsic Properties of Doped Lanthanum Manganite

1995 ◽  
Vol 401 ◽  
Author(s):  
G. Jeffrey Snyder ◽  
Ron Hiskes ◽  
Steve DiCarolis ◽  
M. R. Beasley ◽  
T. H. Geballe
Keyword(s):  
High Temperature ◽  
Electrical Transport ◽  
Small Polaron ◽  
Intrinsic Property ◽  
Lanthanum Manganite ◽  
Perovskite Manganites ◽  
Itinerant Electron ◽  
Intrinsic Properties ◽  
Electrical Transport Properties ◽  
Polaron Hopping

AbstractAn investigation designed to display the intrinsic properties of perovskite manganites was accomplished by comparing the behavior of bulk samples with that of thin films; the results show the "colossal magneto resistance" at very low temperatures is not an intrinsic property of the thermodynamically stable 1/3 doped material. Epitaxial 1500 Å films of perovskite La0.67Ca0.33MnO3 and La0.67Sr0.33MnO3 were grown by solid source chemical vapor deposition on LaA1O3 and post annealed in oxygen at 950°C. Crystals were prepared by LASER heated pedestal growth. The magnetic and electrical transport properties are essentially the same. Below Tc/2 the intrinsic magnetization decreases as T2 (as can be expected for itinerant electron ferromagnets) while the intrinsic resistivity increases proportional to T2. The constant and T2 coefficients of the resistivity are largely independent of magnetic field and alkaline earth element (Ca, Sr or Ba). We identify three distinct types of negative magnetoresistance. The largest effect is observed near the Curie temperature and is likely to be due to magnetic critical scattering. There is also magnetoresistance associated with the net magnetization of polycrystalline samples. The high temperature (above Tc) resistivity of La0.67Ca0.33MnO3 is consistent with small polaron hopping conductivity with a transition at 750K, while La0.67Sr0.33MnO3 does not exhibit activated conductivity until about 500K, well above Tc. The limiting low and high temperature resistivities may place a limit on the maximum possible magnetoresistance of these materials.

ELECTRICAL TRANSPORT AND STABILITY OF TMxSn1-x AMORPHOUS ALLOYS (TM = Fe, Co, Ni)

1980 ◽  
Vol 41 (C8) ◽  
pp. C8-477-C8-480
Author(s):  
G. Marchal ◽  
J. F. Geny ◽  
Ph. Mangin ◽  
Chr. Janot
Keyword(s):  
Electrical Transport ◽  
Amorphous Alloys
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