Influence of Thickness on the Magnetic and Magnetotransport Properties of Epitaxial La0.7Sr0.3MnO3 Films Deposited on STO (0 0 1)

Epitaxial La0.7Sr0.3MnO3 films with different thicknesses (9–90 nm) were deposited on SrTiO3 (0 0 1) substrates by pulsed laser deposition. The films have been investigated with respect to morpho-structural, magnetic, and magneto-transport properties, which have been proven to be thickness dependent. Magnetic contributions with different switching mechanisms were evidenced, depending on the perovskite film thickness. The Curie temperature increases with the film thickness. In addition, colossal magnetoresistance effects of up to 29% above room temperature were evidenced and discussed in respect to the magnetic behavior and film thickness.

Download Full-text

Annealing Condition Effects on the Structural Properties of FePt Nanoparticles Embedded in MgO via Pulsed Laser Deposition

Nanomaterials ◽

10.3390/nano11010131 ◽

2021 ◽

Vol 11 (1) ◽

pp. 131

Author(s):

Tingting Xiao ◽

Qi Yang ◽

Jian Yu ◽

Zhengwei Xiong ◽

Weidong Wu

Keyword(s):

Pulsed Laser Deposition ◽

Room Temperature ◽

High Vacuum ◽

Pulsed Laser ◽

Annealing Process ◽

Ultra High Vacuum ◽

Laser Deposition ◽

Fept Nanoparticles ◽

Annealing Conditions ◽

Vacuum Atmosphere

FePt nanoparticles (NPs) were embedded into a single-crystal MgO host by pulsed laser deposition (PLD). It was found that its phase, microstructures and physical properties were strongly dependent on annealing conditions. Annealing induced a remarkable morphology variation in order to decrease its total free energy. H2/Ar (95% Ar + 5% H2) significantly improved the L10 ordering of FePt NPs, making magnetic coercivity reach 37 KOe at room temperature. However, the samples annealing at H2/Ar, O2, and vacuum all showed the presence of iron oxide even with the coverage of MgO. MgO matrix could restrain the particles’ coalescence effectively but can hardly avoid the oxidation of Fe since it is extremely sensitive to oxygen under the high-temperature annealing process. This study demonstrated that it is essential to anneal FePt in a high-purity reducing or ultra-high vacuum atmosphere in order to eliminate the influence of oxygen.

Download Full-text

Processing by Pulsed Laser Deposition and Structural, Morphological and Chemical Characterization of Bi-Pb-Sr-Ca-Cu-O and Bi-Pb-Sb-Sr-Ca-Cu-O Thin Films

Advances in Science and Technology ◽

10.4028/www.scientific.net/ast.75.202 ◽

2010 ◽

Vol 75 ◽

pp. 202-207

Author(s):

Victor Ríos ◽

Elvia Díaz-Valdés ◽

Jorge Ricardo Aguilar ◽

T.G. Kryshtab ◽

Ciro Falcony

Keyword(s):

Thin Films ◽

Pulsed Laser Deposition ◽

Room Temperature ◽

Pulsed Laser ◽

Chemical Characterization ◽

Laser Deposition ◽

Nominal Composition ◽

Deposition Parameters ◽

The Relationship

Bi-Pb-Sr-Ca-Cu-O (BPSCCO) and Bi-Pb-Sb-Sr-Ca-Cu-O (BPSSCCO) thin films were grown on MgO single crystal substrates by pulsed laser deposition. The deposition was carried out at room temperature during 90 minutes. A Nd:YAG excimer laser ( = 355 nm) with a 2 J/pulse energy density operated at 30 Hz was used. The distance between the target and substrate was kept constant at 4,5 cm. Nominal composition of the targets was Bi1,6Pb0,4Sr2Ca2Cu3O and Bi1,6Pb0,4Sb0,1Sr2Ca2Cu3OSuperconducting targets were prepared following a state solid reaction. As-grown films were annealed at different conditions. As-grown and annealed films were characterized by XRD, FTIR, and SEM. The films were prepared applying an experimental design. The relationship among deposition parameters and their effect on the formation of superconducting Bi-system crystalline phases was studied.

Download Full-text