Density of states estimation for soft core system

The density of states (DOSs) for the soft core system is calculated by the multicanonical molecular dynamics simulation. We found the DOS of this system has a concavity. Owing to this concavity, the probability distribution has double peaks near the temperature where the system undergoes the solid-fluid phase transition.ArticleMOLECULAR SIMULATION. 41(10-12):818-821 (2015)journal articl

A theoretical analysis on highly spin-polarized transport of iron nitride Fe_4N

In order to propose a ferromagnet exhibiting highly spin-polarized transport, we theoretically analyzed the spin polarization ratio of the conductivity of the bulk Fe$_4$N with a perovskite type structure, in which N is located at the body center position of fcc-Fe. The spin polarization ratio is defined by $P = (\sigma_\uparrow - \sigma_\downarrow) / (\sigma_\uparrow + \sigma_\downarrow )$, with $\sigma_{\uparrow(\downarrow)}$ being the conductivity at zero temperature of the up spin (down spin). The conductivity is obtained by using the Kubo formula and the Slater-Koster tight binding model, where parameters are determined from the least-square fitting of the dispersion curves by the tight binding model to those by the first principles calculation. In the vicinity of the Fermi energy, $|P|$ takes almost 1.0, indicating perfectly spin-polarized transport. In addition, by comparing Fe$_4$N to fcc-Fe (Fe$_4$N$_0$) in the ferromagnetic state with the equilibrium lattice constant of Fe$_4$N, it is shown that the non-magnetic atom N plays an important role in increasing $|P|$.Comment: 4 pages, 2 figures, accepted for publication in Phys. Rev.

Electronic structure and magnetism of intermetallic mixed compound Mn₄N₁₋xCx

By applying the recursion method to the intermetallic mixed compound Mn₄N₁₋xCx with cubic perovskite-type structure we investigate the effects of substitution of C atoms for N atoms on the electronic structure and the magnetic properties of Mn₄N. By calculating the DOS's for the ferrimagnetic states of both Mn₄N and Mn₄N₀.₇₅C₀.₂₅ we have determined the magnetic moments at two types of Mn site, Mn(I)(corner site) and Mn(II) (face center site), which are antiparallel to each other. The obtained magnetic moment of Mn(I) in Mn₄N₀.₇₅C₀.₂₅ is found to be the same with that in Mn₄N while the absolute value of Mn(II) moment increases by the substitution of C atoms. As the result the total ferromagnetic moment decreases by the substitution of C atoms. These results are in good agreement with the observations.Article信州大学理学部紀要 30(1): 25-36(1995)departmental bulletin pape

Increased Plasma Levels of Platelet Factor 4 and β-thromboglobulin in Women with Recurrent Pregnancy Loss

Thrombosis in decidual vessels is one of the mechanisms of pregnancy loss. However, few studies have assessed the relation between platelet activation, which is known to cause of thrombosis, and recurrent pregnancy loss (RPL). We investigated platelet activation in women with RPL compared to controls by measuring plasma levels of platelet factor 4 (PF4) and β-thromboglobulin (βTG), and assessed correlations between PF4/βTG and coagulative risk factors associated with RPL. The study group included 135 women who had experienced two or more consecutive pregnancy losses. The control group included 28 age-matched healthy women who had never experienced pregnancy loss. PF4 and βTG plasma levels were significantly higher in the women with RPL than controls (PF4: 14.0 [8.0-20.0] vs. 9.0 [6.0-12.0] ng/ml, p=0.043; βTG: 42.0 [24.3-59.8] vs. 31.5 [26.6-36.4] ng/ml, p=0.002). There was a significant association between βTG and anti-phosphatidylethanolamine antibody immunoglobulin M (aPE IgM) (p=0.048). Among the women with RPL, 18 of those who were positive for PF4 (45%) and 18 of those who were positive for βTG (37%) were negative for all known coagulative risk factors associated with RPL. Measurements of PF4 and βTG may be important because they help identify women who are at risk of RPL