Papers by Keyword: Weak Localization

Abstract: Magnetoresistive effect and electrotransport properties of Ni_х(MgO)_100-х (x: 21-48 at.%) granular composites have been investigated. It is found that prepercolated composites (x < 24 at.%) do not exhibit magnetoresistive properties. After percolation threshold (x: 27-29 at.%) the composites exhibit isotropic negative magnetoresistance (-0,2 %) which has not tunneling nature. Also weak localization is realized in these samples at temperatures below 100 K. At high metal concentration (32 at.% < x) the composites exhibit anisotropic magnetoresistance.

Abstract: We present temperature dependent magnetoresistance measurements on the 2-dimensional electron gas of epitaxially grown AlGaN/GaN heterojunctions on silicon (Si). We report on the quantum correction to the classical conductance. In particular we found weak localization, electron-electron-interaction, and Shubnikov-de Haas oscillations. The results verify the high material quality of the investigated GaN on silicon.

Abstract: We report magnetotransport measurements in single epitaxial graphene layers grown on the C-face of an 8° off-axis 4H-SiC substrate using high temperature annealing conditions with a graphite cap covering the sample. The graphene sheets were found p-type doped, with mobilities varying between 1000 and 11000 cm²/V.s from device to device at 1.6 K. We examine the signature of weak localization and universal conductance fluctuations at weak magnetic field and we show that the phase coherence lengths extracted from the two phenomena are in satisfactory agreement.