Room Temperature Magnetoresistive Response in CMR Perovskite Manganite Thin Films

1997 ◽  
Vol 494 ◽  
Author(s):  
Michael A. Todd ◽  
Charles Seegel ◽  
Thomas H. Baum
Keyword(s):  
Magnetic Field ◽  
Thin Films ◽  
Vapor Deposition ◽  
Room Temperature ◽  
Chemical Vapor ◽  
Perovskite Manganite ◽  
Film Properties ◽  
Low Field ◽  
A Site ◽  
Deposited Film

ABSTRACTPerovskite-structured LaxSryMnO3 thin-films have been deposited onto LaAlO3 substrates via liquid delivery chemical vapor deposition (LD-CVD) using metal(β-diketonato) precursors, M(thd)x [where M= Ca, Sr, La and Mn, thd = 2,2,6,6-tetramethyl-3,5-heptanedionato and x = 2–3]. Thin films were deposited at temperatures between 500 and 700 °C and subsequently annealed at 1000 °C under O2. These films possess stoichiometries that are: i) vastly different from the La0.67Sr0.33MnO3 compositions commonly reported in the literature and ii) display high temperature, low field responses that may be technologically important. Resistance versus temperature measurements revealed a metal to semiconductor transition at room temperature and above. Hall measurements on a film of La0.35Sr0.24MnO3 displayed a magnetoresistive response (MR) of -10% at 57 °C in a fixed magnetic field of 780 Oe. Based upon our research, the observed film properties are directly related to the deposited film stoichiometry and the best results were observed at Sr / La ratios between 0.30 and 1.0 for A-site deficient LaxSryMnO3 thin-films after thermal annealing.

Room Temperature Magnetoresistance in LaxCaYMnO3 Thin-Films Deposited by Liquid Delivery Chemical Vapor Deposition

1997 ◽  
Vol 495 ◽  
Author(s):  
D. Studebaker ◽  
M. Todd ◽  
G. Doubinina ◽  
C. Seegal ◽  
T. H. Baum
Keyword(s):  
Thin Films ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Room Temperature ◽  
Chemical Vapor ◽  
Organic Chemical ◽  
Crystalline Films ◽  
Commercial Applications ◽  
A Site ◽  
Liquid Delivery

ABSTRACTLiquid delivery, metal-organic chemical vapor deposition (MOCVD) was used to deposit high quality, A-site deficient crystalline films of LaxCayMnO3 where x + y < 1. The properties of the deposited thin-films are strongly dependent upon the film stoichiometry and display magnetoresistance repsonses at or above room temperature. Using Ca doped A-site deficient thin-films, we can shift the metal to insulator transition (Te) in a controlled manner to temperatures that are useful for commercial applications. Further, these films exhibit useful magnetoresistance at room temperature in relatively small applied magnetic fields.

Composition dependence of room temperature 1.54μm Er3+ luminescence from erbium doped silicon:oxygen thin films deposited by electron cyclotron resonance plasma enhanced chemical vapor deposition

1997 ◽  
Vol 486 ◽  
Author(s):  
Jung H. Shin ◽  
Mun-Jun Kim ◽  
Se-Young Seo ◽  
Choochon Lee
Keyword(s):  
Thin Films ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Cyclotron Resonance ◽  
Room Temperature ◽  
Composition Dependence ◽  
Electron Cyclotron Resonance ◽  
Chemical Vapor ◽  
Erbium Doped ◽  
Resonance Plasma

AbstractThe composition dependence of room temperature 1.54 μ Er3+ photoluminescence of erbium doped silicon:oxygen thin films deposited by electron cyclotron resonance plasma enhanced chemical vapor deposition of SiH4 and O2 with concurrent sputtering of erbium is investigated. The Si:O ratio was varied from 3:1 to 1:2 and the annealing temperature was varied from 500 to 900 °C. The most intense Er3+ luminescence is observed from the sample with Si:O ratio of 1:1.2 after 900 °C anneal and formation of silicon nanoclusters embedded in SiO2 matrix. High active erbium fraction, efficient excitation via carriers, and high luminescence efficiency due to high quality SiO2 matrix are identified as key factors in producing the intense Er3+ luminescence.

PINNING MECHANISM AND FLUX MOTION IN YBa2Cu3O7 THIN FILMS

2004 ◽  
Vol 18 (07) ◽  
pp. 999-1006
Author(s):  
ALI IHSAN DEMIREL
Keyword(s):  
Magnetic Field ◽  
Thin Films ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Critical Magnetic Field ◽  
Pinning Mechanism ◽  
Tunneling Electron ◽  
Flux Motion ◽  
Strong Pinning ◽  
Mocvd Technique

The flux creep phenomena and the J c characteristics have been investigated in the YBa 2 Cu 3 O 7 (YBCO) thin films grown by metal organics chemical vapor deposition (MOCVD) technique. The anisotropy of the current density (J c ) is discussed on the basis of the intrinsic pinning model and the anisotropic critical magnetic field (H c2 ). The properties of the high J c and the pinning energy are related with the fine precipitates observed by tunneling electron microscopy (TEM). The strong pinning mechanism affects the amount of the flux motion.

Structure and Physical Properties of Bi4Ti3O12Thin Films Prepared by APMOCVD and RTA

1997 ◽  
Vol 493 ◽  
Author(s):  
H. Wang ◽  
Z. Wang ◽  
S. X. Shang ◽  
M. Wang
Keyword(s):  
Thin Films ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Atmospheric Pressure ◽  
Room Temperature ◽  
Chemical Vapor ◽  
Organic Chemical ◽  
Planar Silicon ◽  
Metal Organic ◽  
Organic Chemical Vapor Deposition

ABSTRACTFerroelectric Bi4Ti3O12 thin films were grown by atmospheric pressure metal-organic chemical vapor deposition. After rapid thermal annealing (RTA), the films have a (001) preferred orientation, The I-V and C-V characteristics were studied, the resistivity were in the rang of 1010∼1013 ω. cm, at room temperature. The memory window is about 3V. These results snow that The Bi4Ti3O12 films prepared at present work are suitable for making ferroelectric FEFETs memories. By using planar silicon processing, the FEFET devices have been fabricated, which shows clearly memory effect under a applied ±5V gate voltage.

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