Electrical and magnetic transport study on strain driven ferromagnetic insulating thin film of low doped manganite (original) (raw)
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Journal of Physics Condensed Matter
We report the effect of electric current and magnetic field, separately and in conjugation, on the transport behaviour of patterned La0.7Ce0.3MnO3 thin films. In the absence of a magnetic field, a significant reduction in peak resistance (Rp) was found with increasing bias current. This effect is also present when a magnetic field is applied, though the magnitude of the electroresistance (ER = [R(I = 0.05 μA) − R(I = 50 μA)]/R(I = 50 μA)) decreases. The metal–insulator transition temperature (Tp) increases both with increasing current and with magnetic field. We observe an interesting correlation between electric current and magnetic field: the magnetoresistance (MR = [RH=0 − RH=1 T]/RH=0) decreases with increasing bias current, while ER decreases with increasing magnetic field. Both ER and MR show a maximum near Tp. The interesting correlation between these two effects suggests that both these effects arise from the same origin.
Physical Review B
Strain engineering of epitaxial transition metal oxide heterostructures offers an intriguing opportunity to control electronic structures by modifying the interplay between spin, charge, orbital, and lattice degrees of freedom. Here, we demonstrate that the electronic structure, magnetic and transport properties of La 0.9 Ba 0.1 MnO 3 thin films can be effectively controlled by epitaxial strain. Spectroscopic studies and first-principles calculations reveal that the orbital occupancy in Mn e g orbitals can be switched from the d 3z 2 −r 2 orbital to the d x 2 −y 2 orbital by varying the strain from compressive to tensile. The change of orbital occupancy associated with Mn 3d-O 2p hybridization leads to dramatic modulation of the magnetic and electronic properties of strained La 0.9 Ba 0.1 MnO 3 thin films. Under moderate tensile strain, an emergent ferromagnetic insulating state with an enhanced ferromagnetic Curie temperature of 215 K is achieved. These findings not only deepen our understanding of electronic structures, magnetic and transport properties in the La 0.9 Ba 0.1 MnO 3 system, but also demonstrate the use of epitaxial strain as an effective knob to tune the electronic structures and related physical properties for potential spintronic device applications.
International Journal of Innovative Research in Science, Engineering and Technology, 2014
La0.7A0.3MnO3 (where, A = Sr, Ba) manganite nanostructured thin films have been grown on LAO (100) substrate using Chemical Solution Deposition (CSD) technique. The Insulator-Metal (I-M) transition temperature, TP of ~368K and ~330K were obtained for LSMO and LBMO films respectively. Magnetoresistance (MR) vs. Field (H) isotherms reveal that MR enhances in the vicinit of TP and decreases at low temperature. The current-voltage (I-V) measurements carried out on these films in the temperature range 82K - 300K shows a linear I-V behavior up to 300K for LSMO film with a slight non-linearity at room temperature. The LBMO film exhibits an unusual non-linearity in I- V characteristics in the temperature range studied which may be attributed to inhomogeneous distribution of strain resulting due to the nonuniform microstructure of LBMO film. Fitting of the electrical transport measurements in shows that, the Spin-flip scattering becomes dominant around TP in these film which is also reflecte...
Applied Physics Letters, 2007
Electrical transport and magnetic properties of epitaxial 500 Å La 0.67 Sr 0.33 MnO 3 (LSMO) thin films, grown on different substrates having different lattice strains, are found to exhibit strong correlation with Jahn-Teller (JT) strain. Our study reveals a sufficiently large JT strain even gives rise to distinct insulating state in LSMO films even below the respective para-ferromagentic Curie temperature, which is a contradiction with the established phase diagram of Sr doped manganites. We have presented a microscopic model for the analysis of our data instead of the usual expansion around the undistorted state generally in use in the literature. The model incorporates two relevant e g orbitals (and their ordering thereof) and the effect of both JT and bulk strain on the transition temperature via double exchange.
Substrate dependent transport and magnetotransport in manganite multilayer
Physica B-condensed Matter, 2011
We report magnetotransport properties of La 0.5 Pr 0.2 Sr 0.3 MnO 3 (LPSMO) {5 layers}/La 0.5 Pr 0.2 Ba 0.3 MnO 3 (LPBMO) {4 layers} manganite multilayers grown on single crystalline STO (h 0 0) and NGO (h 0 0) substrates using pulsed laser deposition (PLD) technique. An appreciable magnetoresistance (MR) $ 56% (80 kOe field) at room temperature (RT) is exhibited by the heterostructure deposited on STO substrate having field coefficient of resistance (FCR) $ 35% (100 Oe) while the multilayer deposited on NGO substrate exhibits MR $ 61% (80 kOe field) and FCR $ 18% (5 kOe) at RT. The observed values of temperature coefficient of resistance (TCR) are $ 3.15% and 2.77% at RT for the multilayers grown on STO and NGO substrates, respectively. A comparison of the field sensitivity of the multilayered structure studied with those reported for LPSMO/Al 2 O 3 /LPSMO (FCR $ 20% at 220 K) and LPSMO/STO film (FCR $ 13% at 250 K) shows that the multilayer exhibits higher field sensitivity, which can be attributed to the improved LPSMO-LPBMO interfaces. In this communication, the results of the structural, transport and magnetotransport studies on LPSMO/LPBMO multilayered systems have been discussed.
Low-temperature magnetic and transport anisotropy in manganite thin films
Journal of Physics: Condensed Matter, 2009
The stability of striped magnetic phases in films of La 1−x A x MnO 3 perovskites is investigated. A variational analysis is developed for different film thicknesses at fixed hole density (x = 0.3) and the competition among magnetic phases as a function of the transfer integral and the temperature is analyzed. The stabilization of an in-plane striped magnetic phase is observed with reducing the film thickness at low temperatures below the metal-insulator transition temperature. Within the adopted variational scheme, treating perturbatively the residual electron-phonon interaction, the dependence of the in-plane resistivity on temperature for different thicknesses is calculated. At low temperatures, due to the striped magnetic phase, the resistivity shows an important in-plane anisotropy. The obtained results are found to be consistent with experiments.
Resistivity of Manganite Thin Film Under Strain
Journal of Superconductivity and Novel Magnetism, 2019
A complex study of the electron transport and magnetic characteristics of epitaxial manganite films La0.7Ba0.3MnO3 (LBMO) was carried out under conditions of the crystal structure tension caused by a mismatch between the parameters of the LBMO crystal and the substrate. The epitaxial thin films with the thickness 40-100 nm were grown by pulsed laser deposition at T = 700-800 °C in pure oxygen pressure 0.3-1 mbar. The substrates (110) NGO, (001) STO, (001) LAO, and (001) LSAT were used. By comparison of the lattice parameter of LBMO targets with substrate's one, the lattice mismatches were derived. We used substrates in which the lattice parameter was less than for the LBMO crystal one. It is shown that the temperature dependence of the film resistance in the low-temperature region does not depend on the film stress and is in good agreement with the calculation that takes into account the interaction of carriers with magnetic excitations in the presence of strongly correlated electron states. A nonmonotonic temperature dependence of the resistance of an LBMO film deposited on ferroelectric crystals PMN-PT that was observed. This feature is typical for manganites, and indicating the presence of ferromagnetism in the system was observed.
Epitaxial growth and strain of manganite thin films
Materials Science and Engineering B-advanced Functional Solid-state Materials, 1998
Thin films of La 1 − x Sr x MnO 3 (x=0.4) were fabricated using pulsed laser deposition (PLD) method on various substrates for investigation of the effect of strain induced by lattice mismatch on the electro-magnetic properties. The growth conditions were optimized on SrTiO 3 substrate which has the best lattice matching ( + 0.9%) among the substrates used in this study. The resistivity and magnetization of thick films ( \6 nm) on SrTiO 3 were comparable to those of bulk single crystals. With increasing the lattice mismatch by using LaAlO 3 (−2.0%), the resistivity increased to show insulating behavior caused by biaxial strain due to coherent epitaxial growth. However, further increase of mismatch for NdAlO 3 ( −3.1%) and YAlO 3 ( −4.0%) made it possible to relax partly the strain, resulting in highly conductive films.