325 research outputs found
Theoretical study on magnetic tunneling junctions with semiconductor barriers CuInSe and CuGaSe including a detailed analysis of band-resolved transmittances
We study spin-dependent transport properties in magnetic tunneling junctions
(MTJs) with semiconductor barriers, Fe/CuInSe/Fe(001) and
Fe/CuGaSe/Fe(001). By analyzing their transmittances at zero bias voltage
on the basis of the first-principles calculations, we find that spin-dependent
coherent tunneling transport of wave functions yields a relatively
high magnetoresistance (MR) ratio in both the MTJs. We carry out a detailed
analysis of the band-resolved transmittances in both the MTJs and find an
absence of the selective transmission of wave functions in some
energy regions a few eV away from the Fermi level due to small band gaps in
CuInSe and CuGaSe.Comment: 4 pages, 1 figure, 1 tabl
Feasibility Investigation of Obstacle-Avoiding Sensors Unit without Image Processing
Feasibility of a simple method to detect step height, slope angle, and trench width using four infrared-light-source PSD range sensors is examined, and the reproducibility and accuracy of characteristic parameter detection are also examined. Detection error of upward slope angle is within 2.5 degrees, while it is shown that the detection error of downward slope angle exceeding 20 degrees is very large. In order to reduce such errors, a method to improve range-voltage performance of a range sensor is proposed, and its availability is demonstrated. We also show that increase in trial frequency is a better way, although so as not to increase the detection delay. Step height is identified with an error of Β±1.5βmm. It is shown that trench width cannot be reliably measured at this time. It is suggested that an additional method is needed if we have to advance the field of obstacle detection
Chemical Doping-Driven Giant Anomalous Hall and Nernst Conductivity in Magnetic Cubic Heusler Compounds
Chemical doping efficiently optimizes the physical properties of Heusler
compounds, especially their anomalous transport properties, including anomalous
Hall conductivity (AHC) and anomalous Nernst conductivity (ANC). This study
systematically investigates the effect of chemical doping on AHC and ANC in
1493 magnetic cubic Heusler compounds using high-throughput first-principles
calculations. Notable trends emerge in Co- and Rh-based compounds, where
chemical doping effectively enhances the AHC and ANC. Intriguingly, certain
doped candidates exhibit outstanding enhancement in AHCs and ANCs, such as
(CoNi)FeSn with considerable AHC and ANC values of
~S\,cm and ~A\,mK, respectively, and
(RhRu)MnIn with an AHC of ~S\,cm. In
particular, an extraordinary ANC of ~A\,mK is identified
exclusively in RhCoFeIn, nearly double the maximum value of
~A\,mK observed in the stoichiometric RhCoIn. A
comprehensive band structure analysis underscores that the notable enhancement
in ANC arises from the creation and modification of the energy-dependent nodal
lines through chemical doping. This mechanism generates a robust Berry
curvature, resulting in significant ANCs. These findings emphasize the pivotal
role of chemical doping in engineering high-performance materials, thereby
expanding the horizons of transport property optimization within Heusler
compounds.Comment: 18 pages, 8 figure
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