ScFe$_6$Ge$_4$ with the LiFe$_6$Ge$_4$-type structure (space group $R{\bar{3}}m$), which has a double-layered kagome lattice (18$h$ site) of Fe crystallographically equivalent to that of a well-known topological ferromagnet Fe$_3$Sn$_2$, is newly found to be antiferromagnetic (AFM) with a high N\'eel temperature of $T_{\rm{N}} \approx 650$ K, in contrast to the ferromagnetic (FM) ground state previously proposed in a literature. $^{45}$Sc nuclear magnetic resonance experiment revealed the absence of a hyperfine field at the Sc site, providing microscopic evidence for the AFM state and indicating AFM coupling between the bilayer kagome blocks. The stability of the AFM structure under the assumption of FM intra-bilayer coupling is verified by DFT calculations.
The title compound Ru9Zn7Sb8 was synthesized via a high-temperature reaction from the elements in a stoichiometric ratio, and its structure was solved by a single-crystal X-ray diffraction method. The structure [cubic, space group Fm3̅m, Pearson symbol cF96, a = 11.9062(14) Å (293 K), and Z = 4] adopts a unique 2ahh × 2ahh × 2ahh supercell of a normal half-Heusler phase and shows abnormal features of atomic coordination against the Pauling rule. The formation of this superstructure was discussed in light of the valence electron concentration per unit cell. It is a metallic conductor [ρ(300 K) = 16 μΩ·m], and differential scanning calorimetry revealed that Ru9Zn7Sb8 undergoes a transformation at 1356(1) K and melts, by all indications, congruently at 1386 K. At room temperature, its thermal conductivity is about 3 W/m·K, which is only one-quarter of that of most normal half-Heusler phases. Ru9Zn7Sb8 as well as its analogues of iron-, cobalt-, rhodium-, and iridium-containing compounds are expected to serve as a new structure type for exploring new thermoelectric materials.
We have investigated the noncentrosymmetric superconductor Mo3Al2C prepared by spark plasma sintering, in which the amount of impurity phase was considerably reduced. Another phase transition in the normal state was clearly observed in the spark plasma sintered sample as an abrupt change in the 27Al nuclear magnetic resonance (NMR) spectra and an anomaly in the electrical resistivity. In the transition, a partial gap opening on the Fermi surface is inferred from the decrease in the nuclear spin–lattice relaxation rate \(1/T_{1}\) and the magnetic susceptibility χ below 200 K. The simultaneous presence of two components in the NMR spectra and thermal hysteresis in χ at \({\sim}200\) K indicates the first-order character of the transition. These results imply the formation of the charge-density wave state in Mo3Al2C. In the superconducting state, \(1/T_{1}\) shows a peak just below \(T_{\text{c}}\) and decreases exponentially with temperature, in good agreement with that is expected for the \(s\)-wave superconductor.
We present magnetic torque measurements on the Shastry-Sutherland quantum spin system SrCu2(BO3)2 in fields up to 31 T and temperatures down to 50 mK. A new quantum phase is observed in a 1 T field range above the 1/8 plateau, in agreement with recent NMR results. Since the presence of the DM coupling precludes the existence of a true Bose-Einstein condensation and the formation of a supersolid phase in SrCu2(BO3)2, the exact nature of the new phase in the vicinity of the plateau remains to be explained. Comparison between magnetization and torque data reveals a huge contribution of the Dzyaloshinskii-Moriya interaction to the torque response. Finally, our measurements demonstrate the existence of a supercooling due to adiabatic magnetocaloric effects in pulsed field experiments.
At Japanese higher education institutions, there are many difficulties in receiving medical diagnosis, and students offer the support needs by themselves. So how to apply support need for students with developmental disorders is an issue. students with cognitive imbalance do not always have a high level of “Support Need” and often do not lead to utilize study support the purpose of this study is to examine the characteristics of students who need study support in relation to working memory. We divided 71 students into 2 or 3 groups by based on WMI score (High, Middle, Low) or whether they need study support (HNSG) or not (LNSG). For each of them, the results of relations between WMI score and “(a) Support Need Inventory for University Life (Sasaki, Takahashi, & Takeda, 2018)”, “ (b) AQ Japanese version”, “ (c) CAARS Japanese version” were described by descriptive statistics respectively. And compared between groups. Result; it was confirmed that the deviations of score related to “Digit Span” is relatively large. It seemed that LSNG might have had “Support Need” and Autism Spectrum Disorder like characteristics, but their influence on daily life might have been small.
La-Co co-substituted M-type ferrite magnets have large coercivities and are used as high-performance ferrite magnets in motors. Enhancing the uniaxial magnetic anisotropy of base materials by the substitution of Co2+ improves the coercivity. Since cobalt is a rare element, reducing its use is of great industrial importance. This study deals with the effect of a small amount of Al, Cr, and Mn substitution for Fe on the magnetic properties of La-Co co-substituted M-type ferrites without increasing the amount of Co. The additional substitution of Mn was observed to be advantageous in improving the magnetic anisotropy.
In polar magnets, such as GaV$_4$S$_8$, GaV$_4$Se$_8$ and VOSe$_2$O$_5$, modulated magnetic phases namely the cycloidal and the N\'eel-type skyrmion lattice states were identified over extended temperature ranges, even down to zero Kelvin. Our combined small-angle neutron scattering and magnetization study shows the robustness of the N\'eel-type magnetic modulations also against magnetic fields up to 2 T in the polar GaMo$_4$S$_8$. In addition to the large upper critical field, enhanced spin-orbit coupling produces a variety of modulated phases with sub-10 nm periodicity and a peculiar distribution of the magnetic modulation vectors. Thus, our work demonstrates that non-centrosymmetric magnets with $4d$ and $5d$ electron systems are ideal candidates to host highly compressed magnetic spirals and skyrmions.
