K. M. Satyalakshmi

Ferromagnetic La0.6Pb0.4MnO3 thin films with giant magnetoresistance at 300 K

Highly textured, as-deposited

ENHANCED MAGNETORESISTANCE IN AS-DEPOSITED OXYGEN-DEFICIENT LA0.6PB0.4MNO3-Y THIN FILMS

La_{0.6}Pb_{0.4}MnO_3

GIANT MAGNETORESISTANCE IN La0.6Pb0.4Mn(1−x)TixO3 FILMS: ENHANCEMENT OF MAGNETORESISTANCE DUE TO Ti4+ SUBSTITUTION IN Mn4+ SITES†

thin films have been grown on

LaNiO/sub 3/: a promising material for contact with YBa/sub 2/Cu/sub 3/O/sub 7-x/ thin films

LaAlO_3

Pulsed laser deposition of indium antimonide

by pulsed laser deposition. The films are ferromagnetic metals below 300 K. Giant negative magnetoresistance of over 40% is observed at 300 K at 6 T.

Growth and characterization of laser-deposited Ag-doped YBa2Cu3O7−x thin films on bare sapphire

The La0.6Pb0.4MnO3(LPMO) thin films were in situ deposited at different oxygen partial pressure and at a substrate temperature of 630 degrees C by pulsed laser deposition. The films grown at lower oxygen partial pressures showed an increase in lattice parameter and resistivity and a decrease in the insulator-metal transition temperature as compared to the stoichiometric LPMO thin film grown at 400 mTorr. Further, these oxygen-deficient thin films showed over 70% giant magnetoresistance (GMR) near the insulator-metal transition temperature against the 40% GMR in the case of stoichiometric thin films

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

Abstract Nonmagnetic Ti 4+ ion is substituted for Mn 4+ in La 0.6 Pb 0.4 MnO 3 . The resulting La 0.6 Pb 0.4 Mn (1−x) Ti x O 3 (0 ≤ × ≤ 0.3) crystallizes in rhombohedral structure. The insulator-to-metal transition temperature decreases from 320 K to 92 K as x is varied from 0 to 0.09. Epitaxial films for the compositions x = 0, 0.03, 0.05, and 0.07 are fabricated by pulsed-laser deposition. Magnetoresistance at 6 T is enhanced from 38% for x = 0 to 75% for x = 0.07. The presence of Ti 4+ (d 0 ) ion decreases the Mn-Mn interaction through oxygen and thereby affects the resistivity and magnetoresistance of La 0.6 Pb 0.4 MnO 3 .

Superconducting and non-superconducting oxide multilayers

Epitaxial LaNiO/sub 3/ metallic oxide thin films have been grown on c-axis oriented YBa/sub 2/Cu/sub 3/O/sub 7-/spl delta// thin films on LaAlO/sub 3/ substrates by pulsed laser deposition technique and the interface formed between the two films has been examined by measuring the contact conductance of the same. The specific contact conductance of the interface measured using a modified four probe method was found to be 1.4 to 6/spl times/10/sup 4/ ohm/sup -1/ cm/sup -2/ at 77 K. There are indications that contact conductance can be brought closer to that obtained for noble metal-YBCO interface.

LaNiO3: A promising material for contact with YBa2Cu3O7−δ thin films

Single crystalline oriented films of indium antimonide have been grown on cadmium telluride substrates by the pulsed laser deposition technique. The films were (111) oriented which is the substrate orientation. The composition of the grown films were found to deviate from that of the target owing to loss of antimony during evaporation. This deviation from stoichiometry led to film-substrate reaction, resulting in mixed interface. The antimony deficiency in the films were controlled by correcting the stoichiometry, which led to avoiding mixed interfaces. The stoichiometric films showed good surface morphology and well defined sharp interfaces. The IR transmission spectrum showed sharp band to band absorption and effective detection in the MWIR.

Silver doping: A potential means to grow high quality YBa2Cu3O7−x thin films on bare sapphire

Microstructural and superconducting properties of YBa2Cu3O7−x thin films grownin situ on bare sapphire by pulsed laser deposition using YBa2Cu3O7−x targets doped with 7 and 10 wt% Ag have been studied. Ag-doped films grown at 730°C on sapphire have shown very significant improvement over the undoped YBa2Cu3O7−x films grown under identical condition. A zero resistance temperature of 90 K and a critical current density of 1·2×106 A/cm2 at 77 K have been achieved on bare sapphire for the first time. Improved connectivity among grains and reduced reaction rate between the substrate and the film caused due to Ag in the film are suggested to be responsible for this greatly improved transport properties.