Investigation of Magnetoresistance and Its Anisotropy of Thin Polycrystalline La0.83Sr0.17MnO3La_{0.83}Sr_{0.17}MnO_3 Films in High Pulsed Magnetic Fields

The results on the study of grain boundary effects and influence of film deposition conditions on the magnetoresistance and its anisotropy in polycrystalline $La_{0.83}Sr_{0.17}MnO_3$ films are presented. The magnetoresistance was measured in high pulsed magnetic fields up to 25 T (pulse duration ≈ 0.6 ms) in the temperature range of 120-300 K. A modified Mott hopping model was applied to describe the main behavior of high-field magnetoresistance for both ferromagnetic and paramagnetic phases of the polycrystalline films by taking into account the demagnetization field of the films measured in low magnetic fields perpendicular to film plane. It was also found that to obtain the higher magnetoresistance saturation field at room temperature it is necessary to use the films with smaller crystallites (D ≈ 100 nm). Such films could be used for design of megagauss pulsed magnetic field sensors

Influence of Sr Content on CMR Effect in Polycrystalline La1−xSrxMnO3La_{1-x}Sr_{x}MnO_{3} Thin Films

The magnetoresistance of thin polycrystalline $La_{1-x}Sr_{x}MnO_{3}$ films deposited on lucalox substrate using metal organic chemical vapor deposition technique was investigated in pulsed magnetic fields up to 18 T in the temperature range 100-320 K. The influence of film preparation conditions, ambient temperature variation and Sr content is analyzed in order to determine the optimal conditions for the design of CMR-B-scalar magnetic field sensor based on thin manganite film, operating at room temperature

Electron Transport in Modulation-Doped InAlAs/InGaAs/InAlAs Heterostructures in High Electric Fields

The following peculiarities of electron transport in $In_{0.53}Ga_{0.47}As//In_{0.52}Al_{0.48}As$ quantum wells with δ-Si-doped $In_{0.52}Al_{0.48}As$ barriers at high electric fields are discovered: (1) an enhancement of electron mobility by inserting the InAs phonon wall into the $In_{0.53}Ga_{0.47}As//In_{0.52}Al_{0.48}As$ quantum well, as well as increasing the InAs content in the modulation-doped $In_{0.8}Ga_{0.2}As//In_{0.7}Al_{0.3}As$ heterostructure; (2) a large decrease in electron mobility and a change of electron density with increasing electric field in the range of 1-4 kV/cm; (3) a magnetic field dependence of the threshold electric field for intervalley scattering of electrons; and (4) microwave current oscillations in high electric fields