Giant Magnetoresistance Phenomenon in Laser Ablated La0.6y0.07ca0.33mnox Thin Films

1995 ◽  
Vol 397 ◽  
Author(s):  
Dhananjay Kumar ◽  
R. Kalyanaraman ◽  
J. Narayan ◽  
David K. Christen
Keyword(s):  
Thin Films ◽  
Giant Magnetoresistance ◽  
Lattice Parameter ◽  
Insulator Transition ◽  
X Ray Diffraction ◽  
Metal Insulator Transition ◽  
Metal Insulator ◽  
Spin Dependent Scattering ◽  
Resistance Peak

ABSTRACTMicrostructural and magnetoresistance properties of La0.6Y0.07Ca0.33MnOx (Y-doped LCMO) thin films grown in-situ by pulsed laser ablation have been studied. Transmission election microscopy and x-ray diffraction measurements have shown that the Y-doped LCMO thin films grow epitaxially on (100) LaAl03 substrates and are cubic with a lattice parameter of 3.849 ?. The as-deposited films exhibited a metal-insulator transition at 130 K and a giant magnetoresistance (GMR) at 125 K with a MR ratio (dR/RH) of 1500% in the presence of a magnetic field of 6 Tesla. Such a colossal value of MR ratio for as-deposited Y-doped LCMO films is quite promising keeping in view the fact that these films were unannealed and not optimized. We ascribe this magnetoresistance to spin-dependent electron scattering coupled with the presence of intervening O2. ions across Mn3+ and Mn4+ with suppressed separation between Mn-O layers caused by smaller sized Y-dopant. The effect of annealing on the positive-shift of metal-insulator transition temperature and the improvement in GMR ratio has also been discussed. We also report a non-ohmic response in the Y-doped LCMO films which is observed only in the region of the resistance peak and lends support to a conduction mechanism in these materials based on spin-dependent scattering of electrons.

Metal-insulator transition and giant magnetoresistance in La1−xMnO3−δ thin films and superlattices

1996 ◽  
pp. 244-246
Author(s):  
S. Sundar Manoharana ◽  
M.S. Hegde ◽  
K.M. Satyalakshmi ◽  
V. Prasad ◽  
S.V. Subramanyam
Keyword(s):  
Thin Films ◽  
Giant Magnetoresistance ◽  
Insulator Transition ◽  
Metal Insulator Transition ◽  
Metal Insulator

Metal-insulator transition and giant magnetoresistance in La1 − xMnO3 −δ thin films and superlattices

1996 ◽  
Vol 275 (1-2) ◽  
pp. 244-246 ◽  
Author(s):  
S.Sundar Manoharan ◽  
M.S. Hegde ◽  
K.M. Satyalakshmi ◽  
V. Prasad ◽  
S.V. Subramanyam
Keyword(s):  
Thin Films ◽  
Giant Magnetoresistance ◽  
Insulator Transition ◽  
Metal Insulator Transition ◽  
Metal Insulator

scholarly journals V2O5 Thin Films as Nitrogen Dioxide Sensors †

Sensors ◽  
2018 ◽  
Vol 18 (12) ◽  
pp. 4177 ◽  
Author(s):  
Krystyna Schneider ◽  
Wojciech Maziarz
Keyword(s):  
Thin Films ◽  
Nitrogen Dioxide ◽  
Gas Sensing ◽  
Insulator Transition ◽  
X Ray Diffraction ◽  
Metal Insulator Transition ◽  
Metal Insulator ◽  
Sensor Performance ◽  
V2o5 Thin Films ◽  
Phase Characterization

Vanadium pentoxide thin films were deposited onto insulating support by means of rf reactive sputtering from a metallic vanadium target. Argon-oxygen gas mixtures of different compositions controlled by the flow rates were used for sputtering. X-ray diffraction at glancing incidence (GIXD) and Scanning Electronic Microscopy (SEM) were used for structural and phase characterization. Thickness of the films was determined by the profilometry. It has been confirmed by GIXD that the deposited films are composed of V2O5 phase. The gas sensing properties of V2O5 thin films were investigated at temperatures from range 410–617 K upon NO2 gas of 4–20 ppm. The investigated material exhibited good response and reversibility towards nitrogen dioxide. The effect of metal-insulator transition (MIT) on sensor performance has been observed and discussed for the first time. It was found that a considerable increase of the sensor sensitivity occured above 545 K, which is related to postulated metal-insulator transition.

scholarly journals Controlling metal–insulator transitions in reactively sputtered vanadium sesquioxide thin films through structure and stoichiometry

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Einar B. Thorsteinsson ◽  
Seyedmohammad Shayestehaminzadeh ◽  
Arni S. Ingason ◽  
Fridrik Magnus ◽  
Unnar B. Arnalds
Keyword(s):  
Thin Films ◽  
Local Strain ◽  
Growth Conditions ◽  
Lattice Parameter ◽  
Insulator Transition ◽  
Interstitial Oxygen ◽  
Structural Variations ◽  
Metal Insulator Transition ◽  
Metal Insulator ◽  
Vanadium Sesquioxide

AbstractWe present a study of $$\hbox {V}_{2}\hbox {O}_{3}$$ V 2 O 3 thin films grown on c-plane $$\hbox {Al}_{2}\hbox {O}_{3}$$ Al 2 O 3 substrates by reactive dc-magnetron sputtering. Our results reveal three distinct types of films displaying different metal–insulator transitions dependent on the growth conditions. We observe a clear temperature window, spanning 200 $$^{\circ }$$ ∘ C, where highly epitaxial films of $$\hbox {V}_{2}\hbox {O}_{3}$$ V 2 O 3 can be obtained wherein the transition can be tuned by controlling the amount of interstitial oxygen in the films through the deposition conditions. Although small structural variations are observed within this window, large differences are observed in the electrical properties of the films with strong differences in the magnitude and temperature of the metal–insulator transition which we attribute to small changes in the stoichiometry and local strain in the films. Altering the sputtering power we are able to tune the characteristics of the metal–insulator transition suppressing and shifting the transition to lower temperatures as the power is reduced. Combined results for all the films fabricated for the study show a preferential increase in the a lattice parameter and reduction in the c lattice parameter with reduced deposition temperature with the film deviating from a constant volume unit cell to a higher volume.

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