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.

Effect of Ru Substitution on Structural, Electrical Transport and Magnetoresistive of La2/3Ba1/3MnO3

2006 ◽  
Vol 517 ◽  
pp. 45-48
Author(s):  
A. Huda ◽  
S.A. Halim ◽  
K.P. Lim ◽  
O.J. Lee ◽  
S. Elias ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Electrical Transport ◽  
Doping Concentration ◽  
Resistivity Measurement ◽  
Small Variation ◽  
Structural Pattern ◽  
Variation Range ◽  
Ru Doping ◽  
Xrd Patterns ◽  
Mr Effect

Polycrystalline samples of La0.67Ba0.33(Mn1-xRux)O3 with x = 0, 0.05, 0.1, 0.15 and 0.2 have been prepared using solid state reaction. The effects of doping of Ru at Mn site on La-Ba-Mn- O ceramics, the characteristics and magnetotransport properties of CMR materials are investigated. The magnetoresistance (MR) effect is measured using the four point probe technique. The magnetoresistance defined as MR% = (Ro – RH)/RH x 100% was measured at a magnetic field of H ≤ 1T at 90K, 100K, 150K, 200K, 250K, 270K and 300K for the sample of doping x = 0, 0.05, 0.1, 0.15 and 0.2. Overall, MR drops slowly when temperature rises. All doping concentration gives small variation range (~2.7% to ~26.78%). The electrical property has determined by using standard four-point probe resistivity measurement in a temperature range of 30 K to 300 K. Metalinsulator transition temperature (Tp) shifted to lower temperatures as Ru doping is increased. In this paper the structural pattern and microstructure property have investigated via XRD. XRD patterns show that these systems are in orthorhombic distorted perovskite structures.

scholarly journals Observation of Charge Ordering Signal in Monovalent Doped Nd0.75Na0.25-xKxMn1O3 (0 ≤ x ≤ 0.10) Manganites

2018 ◽  
Vol 7 (4.30) ◽  
pp. 85
Author(s):  
Sufia Aqilah Razali ◽  
Norazilah Ibrahim ◽  
Suhadir Shamsuddin ◽  
Mohamad Zaky Noh
Keyword(s):  
Crystalline Phase ◽  
Electrical Transport ◽  
Resistivity Measurement ◽  
Magnetic Behavior ◽  
Charge Ordering ◽  
Ferromagnetic Phase ◽  
Electrical Resistivity Measurement ◽  
Diffraction Measurement ◽  
The Difference ◽  
Lower Temperature

K doping in the compound of Nd0.75Na0.25-xKxMn1O3 (x = 0, 0.05 and 0.10) manganites have been investigated to study its effect on crystalline phase and surface morphology as well as electrical transport and magnetic properties. The structure properties of the Nd0.75Na0.25-xKxMnO3 manganite have been characterized using X-ray diffraction measurement and it proved that the crystalline phase of samples were essentially single phased and indexed as orthorhombic structure with space group of Pnma. The morphological study from scanning electron microscope showed there was an improvement on the grains boundaries and sizes as well as the compactness with K doping suggestively due to the difference of ionic radius. On the other hand, DC electrical resistivity measurement showed all samples exhibit insulating behavior. However, analysis of dlnρ/dT-1 vs. T revealed the clearly peaks could be observed at temperature 210K for x = 0 and the peaks were shifted to the lower temperature around 190 K and 165 K for x = 0.05 and x = 0.1 respectively, indicate the existence of charge ordering (CO) state in the compound. Meanwhile, the investigation on magnetic behavior showed all samples exhibit transition from paramagnetic phase to anti-ferromagnetic phase with decreasing temperature and the TN was observed to shift to lower temperature suggestively due to weakening of CO state

Electronic Structure and Conductivity Mechanism in Manganite Thin Films Exhibiting Colossal Magnetoresistance

1998 ◽  
Vol 4 (S2) ◽  
pp. 620-621
Author(s):  
Kannan M. Krishnan ◽  
Honglyoul Ju ◽  
C. Nelson
Keyword(s):  
Magnetic Field ◽  
Thin Films ◽  
Electrical Resistance ◽  
Colossal Magnetoresistance ◽  
Magnetic Moments ◽  
Double Exchange ◽  
Perovskite Manganites ◽  
Sensing Applications ◽  
Recent Interest ◽  
Small Change

Perovskite manganites, which have the the general formula R1-xAxMnO3 (R = La, Pr, or Nd and A = Ca, Sr, Ba, or Pb), have generated much recent interest because they exhibit “colossal magnetoresistance” (CMR), i.e. a small change in an applied magnetic field dramatically changes the electrical resistance of the material. Materials that exhibit this effect are being developed for various field-sensing applications but currently, the mechanism by which CMR occurs is not known. Conduction in these materials is explained by the “double exchange” mechanism, where the conductivity is attributed to electrons hopping back and forth between neighboring manganes ions. Such hopping is a maximum when the magnetic moments of the magnese ions are aligned parallel and a minimum when they are aligned antiparallel. In short, these materials show metallic conductivity when they are ferromagnetic and insulating behavior when they are antiferromagnetic. Moreover, they change from metallic to insulating behavior as a function of temperature.

Ferromagnetic Cluster on La2FeMnO6

2014 ◽  
Vol 975 ◽  
pp. 122-127 ◽  
Author(s):  
Petrucio Barrozo ◽  
Nelson O. Moreno ◽  
José Albino Aguiar
Keyword(s):  
Magnetic Field ◽  
Combustion Synthesis ◽  
Electrical Transport ◽  
Room Temperature ◽  
Weak Ferromagnetism ◽  
Electrical Transport Properties ◽  
Temperature Dependent ◽  
Ferromagnetic Cluster ◽  
Xrd Patterns ◽  
Small Polarons

The structural, magnetic and electrical transport properties of La2MnFeO6bulk samples prepared by combustion synthesis have been investigated. The X-ray powder diffraction (XRD) patterns with Rietveld refinement at room temperature shows that samples prepared by combustion synthesis are formed in single phase with an orthorhombic structure space group Pnma (62). The temperature dependent magnetization shows a formation of ferromagnetic cluster at 150K with short range interactions and a long range ferromagnetic order below 75 K. The magnetic field dependence of the magnetization shows a typical paramagnetic behavior at room temperature and a ferromagnetic-like behavior at low temperatures. The low value of the magnetization at high magnetic field can indicate the formation of a weak ferromagnetism or a metamagnetic phase. Results of the temperature dependence of the resistivity show that the transport process in this material can be attributed to small polarons.

Electrical transport properties of FeSe single crystal under high magnetic field

2021 ◽  
Vol 64 (8) ◽  
Author(s):  
HongHui Wang ◽  
ZhaoHui Cheng ◽  
MengZhu Shi ◽  
DongHui Ma ◽  
WeiZhuang Zhuo ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Single Crystal ◽  
Transport Properties ◽  
High Magnetic Field ◽  
Electrical Transport ◽  
Electrical Transport Properties

HIGH FIELD PHASE DIAGRAM OF THE FIELD-INDUCED SUPERCONDUCTING STATE OF λ-(BETS)2FeCl4

2002 ◽  
Vol 16 (20n22) ◽  
pp. 3101-3104
Author(s):  
L. BALICAS ◽  
J. S. BROOKS ◽  
K. STORR ◽  
S. UJI ◽  
M. TOKUMOTO ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Superconducting State ◽  
Ground State ◽  
Electrical Transport ◽  
High Field ◽  
Two Dimensional ◽  
Exchange Field ◽  
Organic Conductor ◽  
Field Phase ◽  
Antiferromagnetic Ground State

We investigate by electrical transport the field-induced superconducting state (FISC) in the organic conductor λ- (BETS) 2 FeCl 4. Below 4 K, antiferromagnetic-insulator, metallic, and eventually superconducting (FISC) ground states are observed with increasing in-plane magnetic field. The FISC state survives between 18 and 41 T, and can be interpreted in terms of the Jaccarino-Peter effect, where the external magnetic field compensates the exchange field of aligned Fe 3+ ions. We further argue that the Fe 3+ moments are essential to stabilize the resulting singlet, two-dimensional superconducting state. Here we provide experimental evidence indicating that this state, as well as the insulating antiferromagnetic ground state, is extremely sensitive to hydrostatic pressure.

scholarly journals Utilization of the microwave electric or magnetic field in the synthesis of monometallic and bimetallic nanoparticles

RSC Advances ◽  
2015 ◽  
Vol 5 (19) ◽  
pp. 14637-14645 ◽  
Author(s):  
Takuya Sumi ◽  
Ralf Dillert ◽  
Satoshi Horikoshi
Keyword(s):  
Magnetic Field ◽  
Microwave Irradiation ◽  
Bimetallic Nanoparticles ◽  
Single Mode ◽  
Microwave Resonator ◽  
Lower Temperature

On preparation of bimetal nanoparticles by using a single-mode microwave resonator, Ag–Ni and Pd–Ag nanocomposites were synthesized under microwave irradiation at 80 centigrade, which was a lower temperature than that for reduction of Ag ion.

scholarly journals Описание колоссального магнитосопротивления La-=SUB=-1.2-=/SUB=-Sr-=SUB=-1.8-=/SUB=-Mn-=SUB=-2-=/SUB=-O-=SUB=-7-=/SUB=- на основе "спин-поляронного" и "ориентационного" механизмов проводимости в парамагнитной области температур

2020 ◽  
Vol 62 (5) ◽  
pp. 669
Author(s):  
С.А. Гудин ◽  
Н.И. Солин
Keyword(s):  
Magnetic Field ◽  
Colossal Magnetoresistance ◽  
Main Role ◽  
Spin Polaron ◽  
Temperature Range ◽  
Conduction Mechanisms ◽  
Theoretical Investigations ◽  
Temperature Dependences ◽  
The Magnetic Field ◽  
Good Agreement

Experimental and theoretical investigations of the resistance of the La1.2Sr1.8Mn2O7 single crystal in magnetic fields from 0 to 90 kOe and in the temperature range from 75 to 300 K has been studied. The magnetoresistance is determined by the “spin-polaron” and “orientation” conduction mechanisms. Using the method of separating contributions to the magnetoresistance from several conduction mechanisms, the observed magnetoresistance of La1.2Sr1.8Mn2O7 manganite in the temperature range of 75-300 K is described, good agreement between the calculated and experimental data is obtained. In a magnetic field of 0 and 90 kOe, the temperature dependences of the size of the spin polaron (in relative units) are calculated for the temperature range 75–300 K. It is shown, that the КМС value is determined by an increase in the linear size of the spin polaron (along the magnetic field), i.e. the main role in the magnitude of the colossal magnetoresistance is made by the change in the size of the magnetic inhomogeneities of the crystal.

Mechanochemical Synthesis and Characteristics of Pb(Mg1/3Nb2/3)O3

2010 ◽  
Vol 177 ◽  
pp. 29-31
Author(s):  
Hao Wu ◽  
Cheng Chen ◽  
Dan Yu Jiang ◽  
Tao Feng ◽  
Qiang Li
Keyword(s):  
Mechanochemical Synthesis ◽  
Milling Time ◽  
Perovskite Phase ◽  
Annealing Treatment ◽  
Ferroelectric Material ◽  
Nano Particles ◽  
Processing Route ◽  
Sem Images ◽  
Lower Temperature ◽  
Xrd Patterns

This paper presents a novel mechanochemical synthesis technique for making nano-structured Pb(Mg1/3Nb2/3)O3 (PMN) ferroelectric material without annealing treatment in a much shorter time and at much lower temperature than those reported in the literature, by using the starting precursors MgO, PbO, and Nb2O5. Specimens of various milling time (3-6h) are characterized from XRD patterns to track and analyze the synthesizing procedure of this mechanochemical processing route. The time used to make the desired PMN powders varies with different milling power. When the constituent oxides were mechanically activated at 1.8KW milling power for 6h, the perovskite phase PMN powder was obtained; while it was formed when milling at 3KW for only 3h. Typical SEM images of the as-received PMN powders show that the powders are aggregated of nano-particles of about 100nm in size.

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