17 research outputs found
Electric-field controlled ferromagnetism in MnGe magnetic quantum dots
Electric-field control of ferromagnetism in magnetic semiconductors at room temperature has been actively pursued as one of the important approaches to realize practical spintronics and non-volatile logic devices. While Mn-doped III-V semiconductors were considered as potential candidates for achieving this controllability, the search for an ideal material with high Curie temperature (Tc>300 K) and controllable ferromagnetism at room temperature has continued for nearly a decade. Among various dilute magnetic semiconductors (DMSs), materials derived from group IV elements such as Si and Ge are the ideal candidates for such materials due to their excellent compatibility with the conventional complementary metal-oxide-semiconductor (CMOS) technology. Here, we review recent reports on the development of high-Curie temperature Mn0.05Ge0.95 quantum dots (QDs) and successfully demonstrate electric-field control of ferromagnetism in the Mn0.05Ge0.95 quantum dots up to 300 K. Upon the application of gate-bias to a metal-oxide-semiconductor (MOS) capacitor, the ferromagnetism of the channel layer (i.e. the Mn0.05Ge0.95 quantum dots) was modulated as a function of the hole concentration. Finally, a theoretical model based upon the formation of magnetic polarons has been proposed to explain the observed field controlled ferromagnetism
Pressure-induced amorphous-to-amorphous configuration change in Ca-Al metallic glasses
Pressure-induced amorphous-to-amorphous configuration changes in Ca-Al metallic glasses (MGs) were studied by performing in-situ room-temperature high-pressure x-ray diffraction up to about 40ā
GPa. Changes in compressibility at about 18ā
GPa, 15.5ā
GPa and 7.5ā
GPa during compression are detected in Ca80Al20, Ca72.7Al27.3, and Ca66.4Al33.6 MGs, respectively, whereas no clear change has been detected in the Ca50Al50 MG. The transfer of s electrons into d orbitals under pressure, reported for the pressure-induced phase transformations in pure polycrystalline Ca, is suggested to explain the observation of an amorphous-to-amorphous configuration change in this Ca-Al MG system. Results presented here show that the pressure induced amorphous-to-amorphous configuration is not limited to f electron-containing MGs
Ultrastructural Morphological Characterization of Right Atrial and Left Ventricular Rat Cardiomyocytes during Postreperfusion Period
Contemporary Technology for Preparing Fiber-Reinforced Composite Materials with a Ceramic Refractory Matrix (Review)
Effect of hypoxia on the composition and state of lipids and oxygen-transport properties of erythrocyte haemoglobin
Freshwater ichthyofauna of Solovetsky Islands (white sea): Natural colonization and recent introductions
Global variability in leaf respiration in relation to climate, plant functional types and leaf traits
Leaf dark respiration (Rdark) is an important yet poorly quantified component of the global carbon cycle. Given this, we analyzed a new global database of Rdark and associated leaf traits. Data for 899 species were compiled from 100 sites (from the Arctic to the tropics). Several woody and nonwoody plant functional types (PFTs) were represented. Mixedāeffects models were used to disentangle sources of variation in Rdark. Areaābased Rdark at the prevailing average daily growth temperature (T) of each site increased only twofold from the Arctic to the tropics, despite a 20Ā°C increase in growing T (8ā28Ā°C). By contrast, Rdark at a standard T (25Ā°C, Rdark25) was threefold higher in the Arctic than in the tropics, and twofold higher at arid than at mesic sites. Species and PFTs at cold sites exhibited higher Rdark25 at a given photosynthetic capacity (Vcmax25) or leaf nitrogen concentration ([N]) than species at warmer sites. Rdark25 values at any given Vcmax25 or [N] were higher in herbs than in woody plants. The results highlight variation in Rdark among species and across global gradients in T and aridity. In addition to their ecological significance, the results provide a framework for improving representation of Rdark in terrestrial biosphere models (TBMs) and associated landāsurface components of Earth system models (ESMs)