Hidetaka Amanai

Bio: Hidetaka Amanai is an academic researcher from Tohoku University. The author has contributed to research in topics: Magnetization & Neutron diffraction. The author has an hindex of 2, co-authored 2 publications receiving 27 citations.

Charge-density-wave destruction and ferromagnetic order in SmNiC2.

Abstract: X-ray scattering and electrical resistivity measurements were performed on ${\mathrm{SmNiC}}_{2}$. Satellite peaks characterized by an incommensurate wave vector (0.5, $\ensuremath{\eta}$, 0) appear below 148 K, at which the resistivity shows an anomaly. The temperature dependence of thermal diffuse scattering above 148 K suggests critical phonon softening. These results indicate the formation of a charge-density-wave. The satellite peaks abruptly disappear and the resistivity sharply decreases when a ferromagnetic transition takes place at 17.7 K.

Lattice Constants, Electrical Resistivity and Specific Heat of RNiC2

Abstract: Anomalous temperature dependence of electrical resistivity was found to be ubiquitous among the compounds RNiC 2 with R = La, Ce, Nd, Sm, Gd, Tb and Er. Lattice parameters were also observed to exhibit anomalous temperature dependence for some of the compounds studied by X-ray diffraction. It is argued that the existence of charge modulated structures is the cause of the former anomalies. The latter anomalies, on the other hand, are likely to be related to the coupling between the lattice and the f-electrons. Results of heat capacity measurements are used to estimate crystal field levels in NdNiC 2 and SmNiC 2 .

Extended phase diagram of R NiC 2 family: Linear scaling of the Peierls temperature

Abstract: Physical properties for the late-lanthanide-based $R{\mathrm{NiC}}_{2}$ ($R=\mathrm{Dy}$, Ho, Er, and Tm) ternary compounds are reported. All the compounds show antiferromagnetic ground state with the N\'eel temperature ranging from 3.4 K for ${\mathrm{HoNiC}}_{2}$ to 8.5 K for ${\mathrm{ErNiC}}_{2}$. The results of the transport and galvanomagnetic properties confirm a charge density wave state at and above room temperature with transition temperatures ${T}_{\mathrm{CDW}}=284$, 335, 366, and 394 K for ${\mathrm{DyNiC}}_{2}$, ${\mathrm{HoNiC}}_{2}$, ${\mathrm{ErNiC}}_{2}$, and ${\mathrm{TmNiC}}_{2}$, respectively. The Peierls temperature ${T}_{\mathrm{CDW}}$ scales linearly with the unit cell volume. A similar linear dependence has been observed for the temperature of the lock-in transition ${T}_{1}$ as well. Beyond the intersection point of the trend lines, the lock-in transition is no longer observed. In this Rapid Communication we demonstrate an extended phase diagram for the $R{\mathrm{NiC}}_{2}$ family.

Alloy Systems and Compounds Containing Rare Earth Metals and Carbon

Abstract: Data on binary, ternary, and multicomponent systems and compounds containing rare earth and carbon known through the beginning of 2017 and methods of their synthesis are critically reviewed. Selected superconducting and magnetic systems are discussed to highlight some more specific and characteristic physical properties of binary and ternary rare earth (transition metal) carbides. Thereby, general trends observed in 16 binary R–C and more than 70 ternary R–T–C (T = d -element) phase diagrams and in the crystal chemistry of more than 400 binary and ternary carbides belonging to more than 60 structure types have been evaluated. Crystal structures of known carbides are briefly analyzed. Three species of carbon occur in these structures: isolated carbon atoms, C 2 units, and C 3 units. Relationships between structure types of binary rare earth carbides as derived from the cubic NaCl type have been evaluated. All 50 known structure types of the R–T–C ternary compounds are classified into two groups: metal-rich carbides (intermetallics) and carbometalates depending on carbon content and M/C ratio (M = metal atoms). Complex anions [T y C z ] n – of different dimensionalities could be identified in the crystal structures of carbometalates. These data can be used for the prediction and synthesis of new rare earth carbides for basic research as well as for technical applications.