Electrical Conductivity and Low-Field Magnetoresistance in La2/3(Ca0.60Ba0.40)1/3Mn1-xVxO3 Prepared by Sol-Gol

2007 ◽  
Vol 121-123 ◽  
pp. 901-904
Author(s):  
Hong Zhang ◽  
Shui Yuan Chen ◽  
Su Zhen Tang ◽  
Wen Pao Ke ◽  
Heng Lai ◽  
...  
Keyword(s):  
Curie Temperature ◽  
Sol Gel ◽  
Experimental Results ◽  
Tunneling Magnetoresistance ◽  
Metal Insulator Transition ◽  
Metal Insulator ◽  
Low Field ◽  
Substitution Ratio ◽  
Curie Temperature Tc ◽  
Evident Difference

La2/3(Ca0.6Ba0.4)1/3Mn1-xVxO3 (x=0, 0.03, 0.05, 0.07, 0.10, 0.15, 0.20) nanoparticles were synthesized using sol-gel technology. The experimental results reveal that, (1) the substitution of V for Mn in La2/3(Ca0.6Ba0.4)1/3Mn1-xVxO3 lowers the Curie temperature TC and the metal–insulator transition temperature TMI; (2) there exists the evident difference between the TC and the TMI for different V substitution ratio; (3) the low-temperature tunneling magnetoresistance and maximum magnetoresistance near Tc increase with the enhancement of V-doping content. Based on the tunneling magnetoresistance model and the percolation model near Curie temperature, the experimental results are explained well.

Magnetic, Electronic - and Magneto - Transport Properties of Nanocrystalline Nd0.6Sr0.4MnO3 Manganites

2009 ◽  
Vol 67 ◽  
pp. 131-136 ◽  
Author(s):  
Kundu Sourav ◽  
Kumar Nath Tapan
Keyword(s):  
Particle Size ◽  
Grain Size ◽  
Transition Temperature ◽  
Curie Temperature ◽  
Transport Properties ◽  
Significant Variation ◽  
Insulator Transition ◽  
Metal Insulator Transition ◽  
Metal Insulator ◽  
Low Field

We have reported in this paper, the effect of grain size in Nd0.6Sr0.4MnO3 .We have investigated the effect of grain size on metal-insulator transition and Curie temperature. We have also reported here the variation of low field magnetoresistance with temperature and grain size. We have observed that the Curie temperature increases monotonically with particle size. The metal insulator transition temperature initially increases with particle size and then gets fixed to a certain value. In these Nd0.6Sr0.4MnO3 nanometric systems, any significant variation of magnetoresistance with particle size is not observed.

Electrical Properties of Ag–La0.67Sr0.33MnO3

2011 ◽  
Vol 675-677 ◽  
pp. 1101-1104 ◽  
Author(s):  
Bao Xin Huang
Keyword(s):  
Small Polaron ◽  
Sol Gel ◽  
Metal Insulator Transition ◽  
Reaction Route ◽  
Conventional Solid State Reaction ◽  
Metal Insulator ◽  
Polaron Hopping ◽  
Ag Addition ◽  
Hopping Model ◽  
Curie Temperature Tc

A series of La0.67Sr0.33MnO3/Ag composites were synthesized using a sol-gel method followed by a conventional solid-state reaction route. The temperature dependence of the magnetic properties and electrical resistivity has been investigated between 80 and 450 K. Except for the sample with x = 0.01, Ag addition has increased the conductivity of this system dramatically. Curie temperature (TC) is almost independent of Ag content and is 352 K for Ag-dopant samples, while the metal–insulator transition temperature TP increases with Ag addition, which is mainly due to the improvement of grain boundaries and opening a new metal conductivity channel caused by the segregation of Ag on the grain surfaces. At low temperature, the ρ - T curves are fitted well by the expression of ρ= ρ0 + ρ2T2 + ρ4.5T4.5 while all data for the above TC can be fitted by using the adiabatic small-polaron-hopping model ρ = ρ0T exp(E/kBT ).

Low field magnetoresistance at the metal–insulator transition in epitaxial manganite thin films

2002 ◽  
Vol 81 (2) ◽  
pp. 319-321 ◽  
Author(s):  
A. de Andrés ◽  
S. Taboada ◽  
J. M. Colino ◽  
R. Ramı́rez ◽  
M. Garcı́a-Hernández ◽  
...  
Keyword(s):  
Thin Films ◽  
Insulator Transition ◽  
Metal Insulator Transition ◽  
Metal Insulator ◽  
Low Field

scholarly journals Role of annealing temperature on the sol–gel synthesis of VO2 nanowires with in situ characterization of their metal–insulator transition

RSC Advances ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 5158-5165 ◽  
Author(s):  
Y.-R. Jo ◽  
S.-H. Myeong ◽  
B.-J. Kim
Keyword(s):  
Sol Gel ◽  
Insulator Transition ◽  
In Situ Characterization ◽  
Metal Insulator Transition ◽  
Metal Insulator ◽  
Nanowire Device ◽  
Sol Gel Synthesis

The single-VO2 nanowire device synthesized via sequential morphological evolutions with oxygen reduction during annealing features a sharp metal-insulator transition.

scholarly journals Correction: Role of annealing temperature on the sol–gel synthesis of VO2 nanowires with in situ characterization of their metal–insulator transition

RSC Advances ◽  
2018 ◽  
Vol 8 (56) ◽  
pp. 31984-31984
Author(s):  
Y.-R. Jo ◽  
S.-H. Myeong ◽  
B.-J. Kim
Keyword(s):  
Annealing Temperature ◽  
Sol Gel ◽  
Insulator Transition ◽  
In Situ Characterization ◽  
Metal Insulator Transition ◽  
Metal Insulator ◽  
Sol Gel Synthesis

Correction for ‘Role of annealing temperature on the sol–gel synthesis of VO2 nanowires with in situ characterization of their metal–insulator transition’ by Y.-R. Jo et al., RSC Adv., 2018, 8, 5158–5165.

Magnetoelastic coupling in strained La0.7Ca0.3MnO3//BaTiO3 Thin Films

2013 ◽  
Vol 1587 ◽  
Author(s):  
A. Alberca ◽  
J. Azpeitia-Urkia ◽  
J. Tornos ◽  
C. Munuera ◽  
F. J. Mompean ◽  
...  
Keyword(s):  
Thin Films ◽  
Phase Separation ◽  
Curie Temperature ◽  
Insulator Transition ◽  
Strong Tendency ◽  
Metal Insulator Transition ◽  
Metal Insulator ◽  
Interfacial Effects ◽  
Magnetoelastic Coupling ◽  
Highly Strained

ABSTRACTIn this paper, we explore the interfacial effects appearing in highly strained La0.7Ca0.3MnO3 (LCMO) ultra-thin films (10-12nm) grown on BaTiO3 (BTO) ferroelectric substrates. The strong tendency to phase separation of this optimally doped manganite contributes to the exotic phenomena observed in magnetism and transport experiments: the so-called Matteucci magnetic loops, magnetic granularity and a second metal insulator transition are observed between 50K and the LCMO Curie temperature, 180K. All these properties define the multiferroic character of these heterostructures, which in LCMO//BTO system is strongly linked to magnetoelastic coupling.

Structure, Magnetoresistance and Electrical Properties of La0.8SrxCa0.2-xMnO3 Compounds

2015 ◽  
Vol 1120-1121 ◽  
pp. 451-455 ◽  
Author(s):  
Shao Qun Jiang ◽  
Gang Wang ◽  
Qi Zhang ◽  
Jun Nan Hou ◽  
Ze Hua Wang
Keyword(s):  
Perovskite Phase ◽  
Sol Gel ◽  
Insulator Transition ◽  
Atomic Diffusion ◽  
Doping Content ◽  
Sintering Process ◽  
Metal Insulator Transition ◽  
Metal Insulator ◽  
Structure Transition ◽  
Average Grain Size

The La0.8SrxCa0.2-xMnO3 (x=0, 0.05 and 0.15) compounds were synthesized by combining sol-gel method and high temperature sintering. The effects of Sr doping content on the microstructure, metal-insulator transition and magnetoresistance (MR) of the La0.8SrxCa0.2-xMnO3 were investigated. The results show that the La0.8SrxCa0.2-xMnO3 exhibit single perovskite phase and the change of Sr doping content can result in phase structure transition. The La0.8Sr0.15Ca0.05MnO3 is rhombohedra structure and the La0.8SrxCa0.2-xMnO3 shows distorted cubic structure when x is no more than 0.05. Increasing Sr doping content causes the degeneration of microstructure homogeneity and density and the decrease of average grain size of the La0.8SrxCa0.2-xMnO3, which can be attributed to the weakening of atomic diffusion during the sintering process. The metal-insulator transition temperature (TMI) of the compounds increases with the decrease of Sr doping content due to the improvement of microstructure. The La0.8Sr0.15Ca0.05MnO3 has the highest MR peak value, which is about 95%. The La0.8Ca0.2MnO3 has the highest room temperature MR, which is about 28%. Moreover, the magnetoresistance of the La0.8Ca0.2MnO3 is very stable between 125~300K.

scholarly journals Tunneling Magnetoresistance in a Two-Layered La2-2xCa1+2xMn2O7Polycrystal

1999 ◽  
Vol 54 (12) ◽  
pp. 695-698
Author(s):  
Tie-Jun Zhou ◽  
Z. Yu ◽  
Y. W. Du
Keyword(s):  
Low Temperature ◽  
Sol Gel ◽  
Tunneling Magnetoresistance ◽  
Gel Method ◽  
Sol Gel Method ◽  
Low Field

Abstract By the sol-gel method, a polycrystal bulk of two-layered La2-2xCa1+2xMn2O7 with x = 0.2 was successfully synthesized. A high sensitive low-field TMR was found at low temperature.

Metal-insulator transition below the Curie temperature in layered manganites

1998 ◽  
Vol 58 (21) ◽  
pp. 14139-14142 ◽  
Author(s):  
D. Y. Xing ◽  
Shi-Jie Xiong ◽  
Duan Feng
Keyword(s):  
Curie Temperature ◽  
Insulator Transition ◽  
Metal Insulator Transition ◽  
Metal Insulator

scholarly journals Effect of The Calcination Process On The Magnetotransport Properties in Co-Precipitation Derived La0.67Ca0.33MnO3 Ceramics

2021 ◽  
Author(s):  
Yule Li ◽  
Ping Yu ◽  
Xiaojin Wang ◽  
Fuxin Ling ◽  
Qingming Chen ◽  
...  
Keyword(s):  
Colossal Magnetoresistance ◽  
Sol Gel ◽  
Insulator Transition ◽  
Precipitation Method ◽  
Metal Insulator Transition ◽  
Metal Insulator ◽  
Calcination Process ◽  
Temperature Ranges ◽  
Lower Temperature ◽  
Co Precipitation

Abstract La0.67Ca0.33MnO3 (LCMO) attracts considerable attention as a quintessential example for colossal magnetoresistance (CMR), metal-insulator transition and related temperature coefficient of resistance (TCR) studies. Here, co-precipitation method was utilized to prepare the LCMO ceramics, whose magnetotransport properties as a function of calcination temperature (Tcal) and calcination time (tcal) were investigated. The magnetotransport properties of these LCMO ceramics were significantly enhanced compared with LCMO derived by sol-gel methods. The TCR of LCMO increased firstly and then decreased as the Tcal increased, whereas the metal-insulator transition temperature (TMIT) shifted towards to the lower temperature. Magnetoresistance (MR) increased as Tcal rose and reached 82.4 % at Tcal = 800 ℃. The mechanism of such magnetotransport properties with different temperature ranges was discussed. The optimal TCR of 32.3%·K-1 in LCMO was prepared with Tcal = 500 ℃ and tcal = 8 h, showing that co-precipitation method would facilitate the potential application of LCMO in infrared detecting and magnetoresistive switching.

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