ﻻ يوجد ملخص باللغة العربية
Intergranular conduction in half metallic CrO2 is known to occur through a combination of spin dependent tunneling (driven by Coulomb Blockade (CB) effects) together with certain spin independent (SI) hopping processes. We present evidence that in polycrystalline CrO2 with enhanced grain size, both these process (CB effect and SI Hopping) are suppressed and the functional form of conductance is best described by Fluctuation Induced Tunneling (FIT) in a wide temperature range. Similar features are observed when grain boundary density is increased by Cr2O3 or Cr2O5.The spin dependent tunneling driven by FIT results in the observation of significant enhancement and monotonic temperature dependence of magnetoresistance. Overall, the magnetotransport measurements in a thus far unexplored crystallographic regime of CrO2 reveal that the functional form of conductance strongly influences its magnetoresistive properties.
Using the recently developed Nth-order muffin-tin-orbital (NMTO) based downfolding technique we revisit the electronic properties of half-metallic ferromagnets, the semi-Heusler NiMnSb and rutile CrO2. The NMTO Wannier orbitals for the Mn-d and Cr-t2
Two-dimensional triangular-lattice materials with spin-1/2 are perfect platforms for investigating quantum frustrated physics with spin fluctuations. Here we report the structure, magnetization, heat capacity and inelastic neutron scattering (INS) re
We compute the tunneling conductance of graphene as measured by a scanning tunneling microscope (STM) with a normal/superconducting tip. We demonstrate that for undoped graphene with zero Fermi energy, the first derivative of the tunneling conductanc
The magnetic and magnetocaloric (MCE) properties were studied in a stuffed honeycomb antiferromagnet GdInO3 polycrystalline. No long-range magnetic ordering was observed with only a sharp upturn in the temperature dependent magnetization curves at TN
We report a study of polycrystalline samples of the family La1-xCdxMnO3+dwith different percentage of Mn4+ ions. X-rays diffraction, Iodometric titration, Raman, Magnetic and Electrical Resistivity measurements provide a general characterisation of t