Structure and Magnetotransport Properties of La2/3Ca1/3MnO3 Thin Films Prepared by Pulsed Laser Deposition

1998 ◽  
Vol 526 ◽  
Author(s):  
O.I. Lebedev ◽  
G. van Tendeloo ◽  
S. Amelinckx ◽  
B. Leibold ◽  
H.-U. Habermeier ◽  
...  

AbstractLa1-xCaxMnO3-δ (LCMO) thin films are grown by pulsed laser deposition on a (100) SrTiO3 substrate at temperatures between 530°C and 890°C. The magnetotransport properties show a high negative magnetoresistance and a shift of the maximum of the R(T) curve as function of temperature. The Curie temperature changes with deposition temperature and film quality in the range of 100-220K. The film quality is characterised by X-ray diffraction and transmission electron microscopy (TEM); film and target compositions were verified by atomic emission spectroscopy. The local structure of the film depends on the growth conditions and substrate temperature. TEM reveals a slight distortion of the film leading to a breakdown of the symmetry from orthorhombic to monoclinic. At the highest growth temperatures, a well defined interface is observed within the LCMO film, parallel to the substrate surface; this interface divides the film into two lamellae with a different microstructure. The lamella close to the substrate is perfectly coherent with the substrate, suggesting that it is strained as a result of the lattice parameter mismatch; the upper lamella shows a typical domain structure with unusual translation interfaces characterised by a displacement vector of the type 1/2 [010]m and 1/2[001]m when referred to the monoclinic lattice.

2001 ◽  
Vol 688 ◽  
Author(s):  
Víctor Rodríguez-Santiago ◽  
Yelitza González ◽  
Félix E. Fernández ◽  
Carl H. Mueller ◽  
Fred W. Van Keuls ◽  
...  

AbstractStrontium barium niobate (SrxBa1−xNb2O6 - SBN) with 0.25≤x≤0.75 is a ferroelectric material of interest for diverse optoelectronic applications. Dielectric properties of bulk SBN crystals were comprehensively studied over 30 years ago for a range of compositions and at frequencies up to 30 MHz, but there is little information on properties at higher frequencies. In particular, and up to the best of our knowledge, there are no published results about SBN thin film dielectric properties at high frequencies. For the study reported here, SBN thin films with x = 0.61 were grown on MgO and LaAlO3 substrates by Pulsed Laser Deposition (PLD). Films with good crystallinity and oriented with c-axis normal to the substrate surface were obtained on both types of substrates, while films on MgO had much better texture due to better lattice matching. Interdigital electrode (IDE) capacitors and coupled microstrip phase shifters (CMPS) were fabricated with both types of samples in order to study dielectric response. Capacitance of the IDE capacitors was measured at 1 MHz as a function of temperature and bias voltage, revealing very low losses but poor capacitance tunability, particularly for samples on MgO. Response of the CMPS structures was measured at room temperature and at high frequencies, up to 21 GHz. Insertion losses were measured up to 28 GHz.


2000 ◽  
Vol 658 ◽  
Author(s):  
Trong-Duc Doan ◽  
Cobey Abramowski ◽  
Paul A. Salvador

ABSTRACTThin films of NdNiO3 were grown using pulsed laser deposition on single crystal substrates of [100]-oriented LaAlO3 and SrTiO3. X-ray diffraction and reflectivity, scanning electron microscopy, and atomic force microscopy were used to characterize the chemical, morphological and structural traits of the thin films. Single-phase epitaxial films are grown on LaAlO3 and SrTiO3 at 625°C in an oxygen pressure of 200 mTorr. At higher temperatures, the films partially decompose to Nd2NiO4 and NiO. The films are epitaxial with the (101) planes (orthorhombic Pnma notation) parallel to the substrate surface. Four in-plane orientational variants exist that correspond to the four 90° degenerate orientations of the film's [010] with respect to the in-plane substrate directions. Films are observed to be strained in accordance with the structural mismatch to the underlying substrate, and this leads, in the thinnest films on LaAlO3, to an apparent monoclinic distortion to the unit cell.


RSC Advances ◽  
2017 ◽  
Vol 7 (50) ◽  
pp. 31327-31332 ◽  
Author(s):  
K. Wang ◽  
M. H. Tang ◽  
Y. Xiong ◽  
G. Li ◽  
Y. G. Xiao ◽  
...  

Epitaxial growth of colossal magnetoresistive thin films of La0.7Sr0.3MnO3 (LSMO) has been achieved on TiO2-terminated (001) SrTiO3 (STO) single-crystal substrates using PLD (pulsed laser deposition).


2013 ◽  
Vol 62 (21) ◽  
pp. 216102
Author(s):  
Han Jun ◽  
Zhang Peng ◽  
Gong Hai-Bo ◽  
Yang Xiao-Peng ◽  
Qiu Zhi-Wen ◽  
...  

1999 ◽  
Vol 14 (6) ◽  
pp. 2355-2358 ◽  
Author(s):  
M. H. Corbett ◽  
G. Catalan ◽  
R. M. Bowman ◽  
J. M. Gregg

Pulsed laser deposition has been used to make two sets of lead magnesium niobate thin films grown on single-crystal h100j MgO substrates. One set was fabricated using a perovskite-rich target while the other used a pyrochlore-rich target. It was found that the growth conditions required to produce almost 100% perovskite Pb(Mg1/3Nb2/3)O3 (PMN) films were largely independent of target crystallography. Films were characterized crystallographically using x-ray diffraction and plan view transmission electron microscopy, chemically using energy dispersive x-ray analysis, and electrically by fabricating a planar thin film capacitor structure and monitoring capacitance as a function of temperature. All characterization techniques indicated that perovskite PMN thin films had been successfully fabricated.


2004 ◽  
Vol 853 ◽  
Author(s):  
Naoki Wakiya ◽  
Toyokazu Nagamune ◽  
Kazuo Shinozaki ◽  
Nobuyasu Mizutani

ABSTRACTThe influence of an in-situ magnetic field on the plume during pulsed laser deposition (PLD) to prepare epitaxial nickel zinc ferrite (NZF) thin films were investigated. An air core coil (solenoid coil) was installed between a target and a substrate, and up to 43 mT of magnetic field was generated by direct current (DC)(Dynamic Aurora PLD method). Application of magnetic field brought about following structural and property changes;(1) deposition rate was almost doubled, (2) the concentration of Ni and Zn in the film was decreased, (3) lattice parameter was unchanged, and (4) magnetization and coercivity was increased. Since deposition rate was increased by application of magnetic field, films with same thickness was also prepared without magnetic field, however, magnetic properties were unchanged. This indicates that application of in-situ magnetic field improved magnetic properties.


1992 ◽  
Vol 285 ◽  
Author(s):  
Allan E. Day ◽  
Samuel J.P. Laube ◽  
M.S. Donley ◽  
J.S. Zabinski

ABSTRACTNiobium diselenide has potential for use as a conductive lubricant, but to achieve the optimal properties of low friction coefficient, high conductivity and oxidation resistance, the SeJNb ratio and crystallinity must be carefully controlled. It has been shown that Pulsed Laser Deposition (PLD) permits the required degree of control, even over films with complex stoichiometries. (4–8). In this study, PLD was used to grow stoichiometric, crystalline thin films of niobium diselenide and to study the effects of laser deposition parameters on film properties. Film chemistry and crystallinity were evaluated using XPS, RBS, and glancingangle XRD. Friction and wear measurements were taken on a ball-on-flat tribometer. The deposition apparatus incorporates a fully computerized data acquisition and control system that facilitated the correlation of the laser deposition parameters to film properties. This study has shown that film chemistry could be changed from substoichiometric to superstoichiometric and crystallinity varied between amorphous to highly crystalline by appropriate choice of PLD parameters. The property correlations and acquisition system that permitted the identification of the optimal growth conditions will be described.


1999 ◽  
Vol 572 ◽  
Author(s):  
Philippe Mérel ◽  
Mohamed Chaker ◽  
Henri Pépin ◽  
Malek Tabbal

ABSTRACTA hybrid Pulsed Laser Deposition system was developed to perform epitaxial growth of GaN on sapphire(0001). This system combines the laser ablation of a cooled Ga target with a well-characterized atomic nitrogen source. Taking advantage of the flexibility of this unique deposition system, high quality GaN thin films were deposited by optimizing both the laser intensity and the nitrogen flux. To date, our best GaN films show a FWHM of the GaN(0002) rocking curve peak equal to 480 arcsec. This result has been obtained at a laser intensity of I = 7×107 W/cm2, a substrate temperature of 800°C and under Ga-rich growth conditions.


Author(s):  
Boscope M. K. Sze ◽  
C. N. Wong ◽  
K. H. Wong

Thin films of Ce0.8Gd0.2O2 and Ce0.8Sm0.2O2 oxide electrolytes have been fabricated by pulsed laser deposition on (100)LaAlO3 substrates at temperature from 300 °C to 700 °C and under 100 mTorr oxygen ambient pressure. The crystal structure, crystallinity and lattice parameters of the as-deposited films are investigated by X-ray diffraction. High quality epitaxial and polycrystalline films are obtained at different growth conditions. We have made impedance measurements on these films in the temperature range from 300 °C to 850 °C. Our results reveal a mark increase in the ionic conductivity of these films in comparison with those of the corresponding bulk materials. The observed enhancements are closely related to the crystallinity of the films. Conductivities of 0.1 S/cm or higher for Ce0.8Gd0.2O2 and Ce0.8Sm0.2O2 are obtained at 500 °C. We have demonstrated that in utilizing these thin films solid oxide fuel cells operating at below 500 °C are possible.


2010 ◽  
Vol 638-642 ◽  
pp. 2921-2926 ◽  
Author(s):  
Tomohiro Yoshitake ◽  
Tsuyoshi Yoshitake ◽  
Kazushi Sumitani ◽  
Ryota Ohtani ◽  
You Nakagawa ◽  
...  

We have previously reported that -AlN crystallites with diameters of 0.5–1 µm were occasionally grown on sapphire(0001) by pulsed laser deposition, which implied that the migration mobility of the species deposited on the substrate surface might be an insufficient for the film growth of -AlN. In the present study, in order to enhance the crystal growth of -AlN, sapphire(0001) substrates with an atomically smoothness (step-sapphire) were employed. The growth conditions of - and -AlN extended to higher nitrogen-pressures, as compared to those using normal surface sapphire(0001) substrates (normal-sapphire). This is due to the enhancement in the mobility of the deposited species on the substrate surface.


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