Electronic Properties Of La0 Research Articles

Effect of Ni-doping on the structural, magnetic, and electronic properties of La0.2Sr0.8MnO3 perovskite

Effect of Ni-doping on the structural, magnetic, and electronic properties of La0.2Sr0.8MnO3 perovskite

Atomic‐Scale Control of Electronic Structure and Ferromagnetic Insulating State in Perovskite Oxide Superlattices by Long‐Range Tuning of BO6 Octahedra

AbstractControl of BO6 octahedral rotations at the heterointerfaces of dissimilar ABO3 perovskites has emerged as a powerful route for engineering novel physical properties. However, its impact length scale is constrained at 2–6 unit cells close to the interface and the octahedral rotations relax quickly into bulk tilt angles away from interface. Here, a long‐range (up to 12 unit cells) suppression of MnO6 octahedral rotations in La0.9Ba0.1MnO3 through the formation of superlattices with SrTiO3 can be achieved. The suppressed MnO6 octahedral rotations strongly modify the magnetic and electronic properties of La0.9Ba0.1MnO3 and hence create a new ferromagnetic insulating state with enhanced Curie temperature of 235 K. The emergent properties in La0.9Ba0.1MnO3 arise from a preferential occupation of the out‐of‐plane Mn d3z2−r2 orbital and a reduced Mn eg bandwidth, induced by the suppressed octahedral rotations. The realization of long‐range tuning of BO6 octahedra via superlattices can be applicable to other strongly correlated perovskites for exploring new emergent quantum phenomena.

Effect of sintering temperature on electronic properties of nanocrystalline La0.7Sr0.3MnO3

The effect of sintering temperature on the magnetic and electronic properties of La0.7Sr0.3MnO3 (LSMO) synthesized by the citrate gel technique is introduced. The single phase nature of all the sintered samples of La0.7Sr0.3MnO3 powder was confirmed by x-ray diffraction. Sintering temperature plays an important role in controlling the grain size. The morphology results show an increment in the average grain size of LSMO because of the grain growth as the sintering temperature increases. The chemical composition of La0.7Sr0.3MnO3 and oxidation states of the elements has been confirmed using x-ray photoelectron spectroscopy. The core level spectra of all elements were studied in detail. The study of valence band spectra revealed the effect of grain size on the degree of hybridization of Mn eg and O 2p orbitals. This effect of grain size is accountable for change in ferromagnetic to paramagnetic transition temperature (TC), resistivity, magnetic properties, and density of states at the Fermi level.

Magnetic and electronic properties of La0.7Ca0.3MnO3/h-YMnO3 bilayer

La0.7Ca0.3MnO3/h-YMnO3 (h ∼ hexagonal) bilayer thin films are grown using pulsed laser deposition technique and magnetic/band-offset measurements are performed to explore the magnetic/electronic properties. The bilayer displays the signatures of the ferromagnetic (FM) La0.7Ca0.3MnO3 layer and antiferromagnetic (AFM) h-YMnO3 layer. The uncompensated spins at the interface of FM/AFM layers caused exchange bias effect. The vertical and horizontal shift in field cooled isothermal magnetization curves below the AFM transition temperature shows dependence on the sign of the cooling magnetic field. Type-II band alignment at the interface of bilayer is realized through valence band offset and conduction band offset values estimated from the photoemission results.

Double Exchange viat2gOrbitals and the Jahn-Teller Effect in FerromagneticLa0.7Sr0.3CoO3Probed by Epitaxial Strain

The magnetic exchange in hole-doped ferromagnetic cobaltates is investigated by studying the magnetic and electronic properties of La0.7Sr0.3CoO3 films as a function of epitaxial strain. We found a strong-coupling double exchange mechanism between Co3+ (4t(2g) 2e(g)) and Co4+ (3t(2g) 2e(g)) high-spin states mediated by t(2g) electrons--in contrast to the moderate coupling provided by the e(g) exchange in manganites. The strong sensitivity of the Curie temperature TC to the bulk compression can be explained by the small bandwidth of the t(2g)-derived states. A strain-induced Jahn-Teller effect is likewise observed. The experimental results clarify the magnetic exchange mechanism in the cobaltates.

Oxygen pressure and thickness dependent lattice strain in La0.7Sr0.3MnO3 films

We report magnetic and electronic properties of La0.7Sr0.3MnO3 (LSMO) thin films epitaxially grown on perovskite substrates by pulsed laser deposition, which are varied with oxygen background pressure and film thickness. The strains of the LSMO films are tuned by the two parameters but their resulting effects are somewhat different. The lattice strain induced by the oxygen pressure suppresses the ferromagnetic transition (TC) and metal–insulator transition (TMI) temperatures. With decreasing film thickness from 110 to 11 nm, however, small changes in both TC and TMI were observed. These results suggest that the physical properties of the LSMO films are strongly dependent on the oxygen content but less sensitive to the film thickness.

The effects of YBa2Cu3O7−δ overlayers on the magnetic and electronic properties of La0.7Sr0.3MnO3

The effects of YBa2Cu3O7−δ (YBCO) cap layers on the magnetic and electronic properties of La0.7Sr0.3MnO3 (LSMO) underlayers was determined by x-ray magnetic circular dichroism and x-ray absorption spectroscopy techniques. The YBCO caps alter the LSMO in a way that effectively decreases the concentration of La at the LSMO/YBCO interface.