Aiming for better extrapolations and predictabilities of thermodynamic properties of materials, new thermodynamic models are implemented in the third-generation Calphad databases. In these models, ...

On the third‐generation Calphad databases: An updated description of Mn

Investigation of effect of annealing temperature on mechanical properties of MgB2

Doping Kondo lattice system CeRu 2 Si 2 with Rh-8% (Ce(Ru 0.92 Rh 0.08 ) 2 Si 2 ) leads to drastic consequences due to the mismatch of the lattice parameters between CeRu 2 Si 2 and CeRh 2 Si 2 . A large variety of experiments clarifies the unusual properties of the ground state induced by the magnetic field from longitudinal antiferromagnetic (AF) mode at H =0 to polarized paramagnetic phase in very high magnetic field. The separation between AF phase, paramagnetic phase and polarized paramagnetic phase varying with temperature, magnetic field and pressure is discussed on the basis of the experiments down to very low temperature. Similarities and differences between Rh and La substituted alloys are discussed with emphasis on the competition between transverse and longitudinal AF modes, and ferromagnetic fluctuations.

Decoupling between Field-Instabilities of Antiferromagnetism and Pseudo-Metamagnetism in Rh-Doped CeRu2Si2 Kondo Lattice

In this work, we study the magnetic impurity resonance states in the superconducting phase of 'magic' angle twisted bilayer graphene for different pairing symmetries. Using a two-orbital model on the emergent honeycomb lattice, we find that the resonance states are dramatically different for [Formula: see text]-wave pairing and topological nontrivial pairings. When the magnetic impurity is located at one site of the emergent honeycomb lattice, i.e. the center of the AB spot of the moire pattern, the spacial distributions of the resonance states will break both the threefold and twofold rotation symmetries of [Formula: see text] point group for pairing symmetries which belong to the irreducible representations of this point group. When the magnetic impurity is located at the center of the emergent honeycomb lattice i.e. the center of the AA spot of the moire pattern, the appearance of resonance peak at the position close to the impurity can be considered as a strong evidence of non-[Formula: see text]-wave pairing.

https://iopscience.iop.org/article/10.1088/1361-648X/aaf626/pdf

Magnetic impurity resonance states for different pairing symmetries in twisted bilayer graphene.

Doping Kondo lattice system CeRu2Si2 with Rh-8% (Ce(Ru0.92Rh0.08)2Si2) leads to drastic consequences due to the mismatch of the lattice parameters between CeRu2Si2 and CeRh2Si2. A large variety of experiments clarifies the unusual properties of the ground state induced by the magnetic field from longitudinal antiferromagnetic (AF) mode at H = 0 to polarized paramagnetic phase in very high magnetic field. The separation between AF phase, paramagnetic phase and polarized paramagnetic phase varying with temperature, magnetic field and pressure is discussed on the basis of the experiments down to very low temperature. Similarities and differences between Rh and La substituted alloys are discussed with emphasis on the competition between transverse and longitudinal AF modes, and ferromagnetic fluctuations.

Decoupling between Field-instabilities of Antiferromagnetism and Pseudo-metamagnetism in Rh-doped CeRu2Si2 Kondo Lattice

We performed scanning tunneling microscopy/ spectroscopy (STM/STS) experiments to investigate Fe substitution effects on the superconductivity (SC) of overdoped Bi2212. The gap-edge peaks in STS spectrum at T≪T
 c
 become inhomogeneous strongly in Fe-doped Bi2212. The spectral weight around zero bias, namely the density of states (DOS) at ∼E
 F
 is partly recovered by substitution of Fe in every position. The recovery of the DOS at ∼E
 F
 can be explained in terms of impurity effects on d-wave SC in the unitarity limit. However, the strong inhomogeneity of gap-edge peaks would be ascribed to different effects due to Fe-substitution.

The Impurity Effects on the Superconducting Gap in the High- T c Superconductor Bi2Sr2CaCu2−x Fe x O 8 + δ Investigated by STM/STS

The structure of disordered (amorphous) Ce x Ru 100 - x alloys have some characteristic features which are inherent in the heavy fermion (dense Kondo) nature. In the Ru rich region ( 15 ⩽ x ⩽ 40 ) , the superconducting behavior appears. With increasing Ru-concentration T c increases monotonically and simultaneously the paramagnetic moment decreases due to increase in the valence fluctuation. The superconductivity in these alloys is thought to be correlated to the 4f-electron state. In the Ce rich region ( x ⩾ 47 ) the electric resistivity at low temperature exhibits the ρ = AT 2 relation with a large coefficient A. This implies that the coherent Kondo state is realized in the low temperature region. Thus, the amorphous Ce–Ru alloy is recognized to be one of the dense Kondo alloys.

Heavy fermion like behavior and superconductivity in amorphous CexRu100-x alloy

Specific heat of amorphous CexRu100−x alloys

Evidence of a heavy fermion state in the disordered Ce-alloy system without translation symmetry

We report the x-ray absorption near edge structure at the Ce L 3 edge for amorphous alloys Ce x Ru 100- x ( x =9, 43, and 80) and a C15 Laves phase compound CeRu 2 , which consists of a couple of peaks characteristic of 4 f 1 and 4 f 0 configurations. This indicates that Ce atoms of these materials are in a mixed valence state. The spectra are fitted to one arctangent and two Lorentzian functions. The Ce valence estimated from relative areas of the Lorentzian peaks varies linearly with Ce content. The transition into the continuum along with both peaks shifts to lower energy with increasing Ce concentration. We find a linear relation between the transition energy and the valence.

Y. Amakai

Papers

The Impurity Effects on the Superconducting Gap in the High- T c Superconductor Bi2Sr2CaCu2−x Fe x O 8 + δ Investigated by STM/STS

Heavy fermion like behavior and superconductivity in amorphous CexRu100-x alloy

Specific heat of amorphous CexRu100−x alloys

Evidence of a heavy fermion state in the disordered Ce-alloy system without translation symmetry

X-ray Absorption Near Edge Structure of Amorphous CexRu100-x