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G M Schott - One of the best experts on this subject based on the ideXlab platform.
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Influence of growth conditions on the Lattice Constant and composition of (Ga, Mn)As
Applied Physics Letters, 2003Co-Authors: G M Schott, Georg Schmidt, Grzegorz Karczewski, Laurens W. Molenkamp, Rafal Jakiela, Adam BarczAbstract:The Lattice Constant and the alloy composition of (Ga,Mn)As are investigated by high-resolution x-ray diffraction and secondary ion mass spectroscopy. The (Ga,Mn)As layers are grown by low-temperature molecular-beam epitaxy under various growth conditions. We find that, while the alloy composition is mainly determined by the Mn cell temperature (TMn), the substrate temperature (Tsub) and the arsenic to gallium flux ratio (As/Ga) strongly influence the Lattice Constant. In particular, layers which have the same composition but different growth parameters have quite different Lattice Constants, caused by the amount of excess As incorporation in the (Ga,Mn)As crystal. This implies that the Lattice parameter of (Ga,Mn)As cannot even serve as a rough measure of the crystal composition. (Ga,Mn)As is therefore an example of a system which does not obey Vegard’s law.
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Lattice Constant variation and complex formation in zincblende gallium manganese arsenide
Applied Physics Letters, 2001Co-Authors: G M Schott, W Faschinger, L W MolenkampAbstract:We perform high resolution x-ray diffraction on GaMnAs mixed crystals as well as on GaMnAs/GaAs and GaAs/MnAs superLattices for samples grown by low-temperature molecular-beam epitaxy under different growth conditions. Although all samples are of high crystalline quality and show narrow rocking curve widths and pronounced finite thickness fringes, the Lattice Constant variation with increasing manganese concentration depends strongly on the growth conditions: For samples grown at substrate temperatures of 220 and 270 °C, the extrapolated relaxed Lattice Constant of Zincblende MnAs is 0.590 nm and 0.598 nm, respectively. This is in contrast to low-temperature GaAs, for which the Lattice Constant decreases with increasing substrate temperature.
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Lattice Constant variation and complex formation in zincblende gallium manganese arsenide
arXiv: Materials Science, 2001Co-Authors: G M Schott, W Faschinger, L W MolenkampAbstract:We perform high resolution X-ray diffraction on GaMnAs mixed crystals as well as on GaMnAs/GaAs and GaAs/MnAs superLattices for samples grown by low temperature molecular beam epitaxy under different growth conditions. Although all samples are of high crystalline quality and show narrow rocking curve widths and pronounced finite thickness fringes, the Lattice Constant variation with increasing manganese concentration depends strongly on the growth conditions: For samples grown at substrate temperatures of 220 and 270 degrees C the extrapolated relaxed Lattice Constant of Zincblende MnAs is 0.590 nm and 0.598 nm respectively. This is in contrast to low temperature GaAs, for which the Lattice Constant decreases with increasing substrate temperature.
L W Molenkamp - One of the best experts on this subject based on the ideXlab platform.
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Lattice Constant variation and complex formation in zincblende gallium manganese arsenide
Applied Physics Letters, 2001Co-Authors: G M Schott, W Faschinger, L W MolenkampAbstract:We perform high resolution x-ray diffraction on GaMnAs mixed crystals as well as on GaMnAs/GaAs and GaAs/MnAs superLattices for samples grown by low-temperature molecular-beam epitaxy under different growth conditions. Although all samples are of high crystalline quality and show narrow rocking curve widths and pronounced finite thickness fringes, the Lattice Constant variation with increasing manganese concentration depends strongly on the growth conditions: For samples grown at substrate temperatures of 220 and 270 °C, the extrapolated relaxed Lattice Constant of Zincblende MnAs is 0.590 nm and 0.598 nm, respectively. This is in contrast to low-temperature GaAs, for which the Lattice Constant decreases with increasing substrate temperature.
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Lattice Constant variation and complex formation in zincblende gallium manganese arsenide
arXiv: Materials Science, 2001Co-Authors: G M Schott, W Faschinger, L W MolenkampAbstract:We perform high resolution X-ray diffraction on GaMnAs mixed crystals as well as on GaMnAs/GaAs and GaAs/MnAs superLattices for samples grown by low temperature molecular beam epitaxy under different growth conditions. Although all samples are of high crystalline quality and show narrow rocking curve widths and pronounced finite thickness fringes, the Lattice Constant variation with increasing manganese concentration depends strongly on the growth conditions: For samples grown at substrate temperatures of 220 and 270 degrees C the extrapolated relaxed Lattice Constant of Zincblende MnAs is 0.590 nm and 0.598 nm respectively. This is in contrast to low temperature GaAs, for which the Lattice Constant decreases with increasing substrate temperature.
Y. Watanabe - One of the best experts on this subject based on the ideXlab platform.
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Temperature dependence of the Lattice Constant in metallic sodium
Journal of Applied Crystallography, 1994Co-Authors: Hiroshi Abe, Ken-ichi Ohshima, T. Sukuki, Y. WatanabeAbstract:The temperature dependence of the Lattice Constant for the parent phase in metallic sodium, which has a body-centred cubic (b.c.c.) structure, has been measured by an X-ray single-crystal diffraction method over a range of 20 to 293 K. An abnormal change of the Lattice Constant at around 40 K is shown, which is attributed to small regions of the low-temperature phase. On the other hand, the value of the full width at half-maximum (FWHM) for the (110)b.c.c. Bragg reflection increased gradually with decreasing temperature and then changed drastically at around 40 K. This result was inconsistent with the neutron diffraction one: the value was Constant down to the phase-transition temperature and changed drastically at that temperature. The FWHM for the X-ray experiment is very sensitive to the size of the specimen and sample mount because the external strain originating from contraction of the sample holder is often introduced into the specimen.
Sebastiaan Van Dijken - One of the best experts on this subject based on the ideXlab platform.
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Nanometer-thick YIG-based magnonic crystals: Bandgap dependence on groove depth, Lattice Constant, and film thickness
Applied Physics Letters, 2020Co-Authors: Huajun Qin, Sebastiaan Van DijkenAbstract:We report on bandgap tuning in magnonic crystals made of nanometer-thick yttrium iron garnet (YIG) films with CoFeB-filled grooves via a variation of the groove depth, Lattice Constant, and film thickness. Using broadband spin-wave spectroscopy, we demonstrate bandgap widening in a 260-nm-thick YIG crystal when the grooves are deepened from half to full film thickness. Importantly, low-loss spin-wave transmission in the allowed bands of the magnonic crystal is almost unaffected by the patterning of fully discrete YIG stripes. Downscaling of the YIG film thickness to 35 nm decreases the bandgap size through a flattening of the spin-wave dispersion relation. We show that a reduction in the Lattice Constant effectively compensates for this trend. Our experimental results are corroborated by micromagnetic simulations, providing relevant information for the design of ultrathin YIG-based magnonic crystals with optimized bandgaps and spin-wave transmission properties.
Lei Zhang - One of the best experts on this subject based on the ideXlab platform.
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Size dependences of Lattice Constant and magnetic properties of Ni nanoplatelets
Materials Chemistry and Physics, 2013Co-Authors: Huazhi Wang, Juanjuan Huang, Lei ZhangAbstract:Abstract Ni plate-like nanoparticles (or nanoplatelets), with a mean diameter in the range from 42 to 130 nm and a thickness of about 10 nm, were synthesized by solution reduction method. Increased crystallite-size dependences of the Lattice Constant and the coercivity were observed. The cause for the variation of the Lattice Constant and the coercivity of Ni nanoplatelets with their size was investigated, respectively.