Comparison of Sol-Gel Derived and Pulsed Laser Deposited Epitaxial La0.67Ca0.33MnO3 Films for IR Bolometer

2004 ◽  
Vol 811 ◽  
Author(s):  
Rickard Fors ◽  
Annika Pohl ◽  
Sergey Khartsev ◽  
Alexander Grishin ◽  
Gunnar Westin
Keyword(s):  
Colossal Magnetoresistance ◽  
Sol Gel ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
Maximum Temperature ◽  
Post Annealing ◽  
Out Of Plane ◽  
Temperature Coefficient Of Resistivity ◽  
Gel Technique ◽  
Sol Gel Films

ABSTRACTEpitaxial La0.67Ca0.33MnO3 films have been prepared on LaAlO3 crystals by pulsed laser deposition (PLD) and by a novel all-alkoxide sol-gel technique. Different out-of-plane lattice parameters are found for the as-prepared films, and scanning electron microscopy shows a more porous structure for sol-gel films as compared to PLD films. These differences are largely removed by post-annealing at 1000 °C. Transport measurements show maximum temperature coefficient of resistivity of 8.2 % K−1 at 258 K (PLD) and 6.1 % K−1 at 241 K (sol-gel) and colossal magnetoresistance at 7 kOe of 35 % at 263 K (PLD) and 32 % at 246 K (sol-gel).

Transport Anisotropy in PLD-Made La0.75Sr0.25MnO3 Films

2000 ◽  
Vol 623 ◽  
Author(s):  
P. Johnsson ◽  
S.I. Khartsev ◽  
A.M. Grishin
Keyword(s):  
Electrical Resistivity ◽  
Low Temperature ◽  
Thick Films ◽  
Anisotropy Parameter ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
Maximum Temperature ◽  
Strong Anisotropy ◽  
Maximum Value ◽  
Temperature Coefficient Of Resistivity

AbstractA sequence of epitaxial La0.75Sr0.25MnO3 (LSMO) films with thickness ranging from 2400 to 50 Å have been prepared by pulsed laser deposition onto (110) SrTiO3 (STO) substrates. Compared with oar previous results on LSMO/STO(100) films [1], films on STO(110) substrates exhibit strong, anisotropy of electrical resistivity p. p measured in [110] direction is comparable with the resistivity of LSMO/STO(100) films while p in [001] direction is 25 times higher than in STO(100) case. The maximum value of anisotropy parameter p[001]/p[110] = 25 is reached for thick films at the low temperature of 90 K. Distinct crossover from 3D to 2D case has been observed. For thick films anisotropy monotonously decreases with the temperature increase. Films thinner than 200 Å exhibit a maximum of anisotropy parameter, which shifts to lower temperatures with the thickness decrease. The maximum temperature coefficient of resistivity (TCR) was found to be around 2% if measured along [001] direction and about 50 % higher in [11O] inplane direction. We explain the observed effects in terms of the crystalline properties of fabricated films.

Colossal Temperature Coefficient of Resistivity in Epitaxial Colossal Magnetoresistive La0.67Ca0.33MnO3 Films

2001 ◽  
Vol 666 ◽  
Author(s):  
S.I. Khartsev ◽  
A.M. Grishin
Keyword(s):  
Temperature Coefficient ◽  
Lattice Mismatch ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
Processing Conditions ◽  
Colossal Magnetoresistive ◽  
Lcmo Film ◽  
Post Annealing ◽  
Temperature Coefficient Of Resistivity ◽  
Film Substrate

ABSTRACTEpitaxial La0.67Ca0.33MnO3(LCMO) films have been grown by pulsed laser deposition technique on three single crystal substrates: LaAlO3, SrTiO3, and NdGaO3 having lattice mismatch with LCMO film of + 1.26 %, - 0.9 %, and + 0.18 %. We found the transport colossal magnetoresistive (CMR) properties were improved with the reduction of a film/substrate mismatch. Processing conditions for LCMO film on NdGaO3substrate were optimized as well as post-annealing process was employed to achieve a superior temperature coefficient of resistivity TCR = 35 %K−1 and the magnetoresistance MR = 66 % at 7 kOe. To our knowledge, these are the record CMR parameters achieved so far.

The impact of different ZnO growth methods on the electrical and optical properties of a n-ZnO/p-GaN:Mg/c-plane sapphire UV LED

RSC Advances ◽  
2014 ◽  
Vol 4 (26) ◽  
pp. 13593-13600 ◽  
Author(s):  
Songül Fiat Varol ◽  
Derya Şahin ◽  
Michael Kompitsas ◽  
Güven Çankaya
Keyword(s):  
Optical Properties ◽  
Sol Gel ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
Zno Films ◽  
Electrical And Optical Properties ◽  
Uv Led ◽  
Gel Technique ◽  
The Impact ◽  
Growth Methods

ZnO films were successfully grown on GaN/sapphire by Pulsed Laser Deposition (PLD) and the sol–gel technique.

Effect of Annealing on Structural and Optical Properties of Pulsed Laser Deposited Titanium Dioxide Thin Films

2009 ◽  
Vol 67 ◽  
pp. 65-70 ◽  
Author(s):  
Gaurav Shukla ◽  
Alika K. Khare
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Pulsed Laser Deposition ◽  
Annealing Temperature ◽  
Ambient Pressure ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
Tio2 Thin Films ◽  
Post Annealing ◽  
Post Annealing Temperature

TiO2 is a widely studied material for many important applications in areas such as environmental purification, photocatalyst, gas sensors, cancer therapy and high effect solar cell. However, investigations demonstrated that the properties and applications of titanium oxide films depend upon the nature of the crystalline phases present in the films, i.e. anatase and rutile phases. We report on the pulsed laser deposition of high quality TiO2 thin films. Pulsed Laser deposition of TiO2 thin films were performed in different ambient viz. oxygen, argon and vacuum, using a second harmonic of Nd:YAG laser of 6 ns pulse width. These deposited films of TiO2 were further annealed for 5hrs in air at different temperatures. TiO2 thin films were characterized using x-ray diffraction, SEM, photoluminescence, transmittance and reflectance. We observed effect of annealing over structural, morphological and optical properties of TiO2 thin films. The anatase phase of as-deposited TiO2 thin films is found to change into rutile phase with increased annealing temperature. Increase in crystalline behaviour of thin films with post-annealing temperature is also observed. Surface morphology of TiO2 thin films is dependent upon ambient pressure and post- annealing temperature. TiO2 thin films are found to be optically transparent with very low reflectivity hence will be suitable for antireflection coating applications.

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