Related papers: Intrinsic tunneling in phase separated manganites
In view of recent experiments, indicating the spatial coexistence of conducting and insulating regions in the ferromagnetic metallic phase of doped manganites, we propose a refined mixed-phase description. The model is based on the…
The influence of a magnetic field on the tunneling of an electron out of a confining plane is studied by a path integral method. We map this 3-d problem on to a 1-d one, and find that the tunneling is strongly affected by the field. Without…
We report the suppression of the magnetic phase transition in La1-xCaxMnO3 close to the localized-to-itinerant electronic transition, i.e. at x = 0.2 and x = 0.5. A new crossover temperature Tf can be defined for these compositions instead…
We investigate electric field effects in thin film microbridges of La$_{0.7}$Ca$_{0.3}$MnO$_3$ with the focus on the regime of metal-insulator transition. A mechanically milled SrTiO$_3$ substrate is used as a backgate dielectric. Inside…
Colossal enhancement of magnetoresistance has been achieved over a broad temperature range which extends upto the room temperature, in ferromagnetic metal-charge ordered insulator manganite multi-layers. The artificially created phase…
A spin-tunnel-junction based on manganites, with La$_{1-x}$Sr$_x$MnO$_3$ (LSMO) as ferromagnetic metallic electrodes and the undoped parent compound LaMnO$_3$ (LMO) as insulating barrier, is here theoretically discussed using double…
Transmission of information using the spin of the electron as well as its charge requires a high degree of spin polarization at surfaces. At surfaces however this degree of polarization can be quenched by competing interactions. Using a…
Thermal fluctuation in magnets will bring temperature-dependent self-energy corrections to the magnons, however, their effects on the topological orders of magnons is not well explored. Here we demonstrate that such corrections can induce a…
Magnetotransport properties of GaMnAs single layers and InGaMnAs/InGaAs superlattice structures were investigated at temperatures from 4 K to 300 K and magnetic fields up to 23 T to study the influence of carriers confinement through…
In recent experiments with a superconducting nanosized Pb bridge formed between a scanning tunneling microscope tip and a substrate, superconductivity has been detected at magnetic fields, which are few times larger than the third (surface)…
The temperature-dependent infrared properties of $\theta$-(BEDT-TTF)$_2$RbZn(SCN)$_4$ were investigated. In the temperatures above the metal-insulator (M-I) transition, the optical conductivity remains finite in the low energy region, but…
We have performed electrical resistivity and DC magnetization measurements as a function of temperature, on polycrystalline samples of phase separated LaPrCaMnO. We have used the General Effective Medium Theory to obtain theoretical…
Ferromagnetic topological insulators exhibit the quantum anomalous Hall effect that might be used for high precision metrology and edge channel spintronics. In conjunction with superconductors, they could host chiral Majorana zero modes…
In this dissertation, thermal and electrical properties of aligned multiwall carbon nanotubes (MWNTs) prepared by thermal decomposition of hydrocarbons have been experimentally studied. The thesis consists of six chapters. Ch1 is an…
We investigate heat and charge transport through a diffusive SIF1F2N tunnel junction, where N (S) is a normal (superconducting) electrode, I is an insulator layer and F1,2 are two ferromagnets with arbitrary direction of magnetization. The…
Mn-rich MnSb$_2$Te$_4$ is a ferromagnetic topological insulator with yet the highest Curie temperature T_C = 45-50 K. It exhibits a magnetic gap at the Dirac point of the topological surface state that disappears above T_C. By scanning…
Magnetite (Fe3O4) based tunnel junctions with turret/mesa structure have been investigated for different barrier materials (SrTiO3, NdGaO3, MgO, SiO2, and Al2O(3-x)). Junctions with a Ni counter electrode and an aluminium oxide barrier…
The influence of ballistic channels superimposed on tunneling conduction channels in magnetic tunnel junctions has been studied in a manganese oxide based tunneling device. Inversion of magnetoresistance has been observed in magnetic tunnel…
The most anisotropic high temperature superconductors like Bi2Sr2CaCu2O8, as well as the recently discovered layered manganite La1.4Sr1.6Mn2O7 are layered metallic systems where the interlayer current transport occurs via sequential…
The authors use two insulator layers in thermotunnel refrigerator to modify the shape of the tunneling barrier so that electrons with high kinetic energy pass it with increased probability. Theoretical analysis show that the overall…