In Ref. 1, Schubert et al. [Phys. Rev. Research 1, 032004 (2019)] reported measurements of the isothermal magnetoresistance of Fe-and Ni-substituted YbRh2Si2, based on which they raised questions about the Kondo destruction description for the magnetic field-induced quantum critical point (QCP) of pristine YbRh2Si2. Here we make three points. Firstly, as shown by studies on pristine YbRh2Si2 in Paschen et al. and Friedemann et al., isothermal crossed-field and single-field Hall effect measurements are necessary to ascertain the evolution of the Fermi surface across this QCP. Because Schubert et al. did not carry out such measurements, their results on Fe-and Ni-substituted YbRh2Si2 cannot be used to assess the validity of the Kondo destruction picture neither for substituted nor for pristine YbRh2Si2. Secondly, when referring to the data of Friedemann et al. on the isothermal crossover of YbRh2Si2, they did not recognize the implications of the crossover width, quantified by the full width at half maximum (FWHM), being linear in temperature, with zero offset, over about 1.5 decades in temperature, from 30 mK to 1 K. Finally, in claiming deviations of Hall crossover FWHM data of Friedemann et al. from the above linear-in-T dependence they neglected the error bars of these measurements and discarded some of the data points. The claims of Schubert et al. are thus not supported by data, neither previously published nor new (Ref. 1). As such they cannot invalidate the evidence that has been reported for Kondo destruction quantum criticality in YbRh2Si2.Quantum criticality is a topic of considerable interest for a variety of strongly correlated electron systems, with antiferromagnetic heavy fermion systems representing a prototype. From extensive experimental measurements across QCPs of several heavy fermion metals, a variety of properties are found 2-16 to be inconsistent with spin-density-wave quantum criticality [17][18][19] , which is based on Landau's framework of order-parameter fluctuations. Instead, they support Kondo destruction quantum criticality 20-22 , which goes beyond the Landau framework through a critical destruction of the static Kondo entanglement. In particular, across the magnetic field-induced QCP in YbRh 2 Si 2 , the linear-response Hall coefficient determined from a crossed-field Hall measurement 3,5 , along with single-field Hall effect 3,5 , magnetoresistance 3,5 , and thermodynamic properties 4 , provided evidence for an extra energy scale, T * , in the T -B plane. This energy scale goes to zero as the QCP is approached from the non-magnetic side. Isothermal magnetotransport and thermodynamic properties undergo a rapid crossover across the T * -line, which extrapolates to a jump in the T = 0 limit, across generations of YbRh 2 Si 2 samples. These properties are in contrast with the po-larization crossover scenario 1 .Recently, Schubert et al. 1 studied the magnetoresistance of Fe-and Ni-substituted YbRh 2 Si 2 . Primarily based on the isothermal behavior of the magnetoresistance in these dope...

We report the discovery of superconductivity on high-quality single crystals of transition-metal pnictides WP grown by chemical vapor transport (CVT) method.Bulk superconductivity is observed at T c = 0.84 K under ambient pressure by electrical resistivity and AC magnetic susceptibility measurements. The effects of magnetic field on the superconducting transitions are studied, leading to a large anisotropy parameter around 2 with the in-plane and out-of-plane upper critical fields of 2,∥ =172 Oe and 2,⊥ =85 Oe, respectively. Our finding demonstrates that WP is the first superconductor in 5d transition-metal at ambient pressure in MnP-type, which will help to search for new superconductors in transition-metal pnictides.

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We report results of isothermal magnetotransport and susceptibility measurements at elevated magnetic fields B down to very low temperatures T on high-quality single crystals of the frustrated Kondo-lattice system CePdAl. They reveal a B*(T) line within the paramagnetic part of the phase diagram. This line denotes a thermally broadened 'small' -to -'large' Fermi surface crossover which substantially narrows upon cooling. At B 0 * = B*(T=0) = (4.6 ± 0.1) T, this B*(T) line merges with two other crossover lines, viz. T p (B) below and T FL (B) above B 0 *. T p characterizes a frustration-dominated spin-liquid state, while T FL is the Fermi-liquid temperature associated with the lattice Kondo effect. Non-Fermi-liquid phenomena which are commonly observed near a 'Kondo destruction' quantum critical point cannot be resolved in CePdAl. Our observations reveal a rare case where Kondo coupling, frustration and quantum criticality are closely intertwined. PACS:Frustrated Kondo lattice systems have recently attracted much attention because of the emergence of exciting novel quantum phases. For example, in Yb 2 Pt 2 Pb, where frustration is caused by the quasi-two-dimensional Shastry-Sutherland lattice structure, a low-temperature phase emerges which most likely is a valence-bond solid [1]. Tetragonal YbRh 2 Si 2 with inherent magnetic frustration shows, when substituted with several % of Ir (for Rh) [2] or Ge (for Si) [3], a non-Fermi liquid (NFL) phase in which the localized 4f -electron -derived magnetic moments are neither ordered nor Kondo screened. This identifies some critical quantum spin-liquid phase in the presence of a 'small' Fermi surface due to the (s, p, d) conduction electrons. Further examples for frustrated Kondo lattice systems are YbAgGe [4] and CeRhSn [5] with hexagonal ZrNiAl structure crystallizing in a distorted Kagome lattice with completely frustrated nearest-neighbor interactions.In order to explore the interplay of the local moments' enhanced zero-point motion due to frustration and their Kondo coupling to the conduction electrons, a 'global' phase diagram (at T = 0) has been proposed which highlights fundamentally different paramagnetic and antiferromagnetic (AF) phases with either 'small' or 'large' Fermi surface (including also the 4f -electronic degrees of freedom) [6][7][8]. It contains a line of AF quantum critical points (QCPs), which intersects or even partially coincides with a 2 nd order localizationdelocalization quantum phase transition of the 4f electrons. The latter was predicted [9-11] to lead to an abrupt change of the Fermi-surface (or charge carrier concentration) which was indeed concluded from de-Haas-van-Alphen (dHvA) measurements on CeRhIn 5 under pressure [12][13][14] and isothermal magnetotransport [15,16] as well as thermodynamic [17] measurements on YbRh 2 Si 2 . The finitetemperature signatures of this abrupt jump in the charge-carrier concentration at the QCP are thermally broadened changes in the afore-mentioned quantities at a crossover line B*(T) [18]. Interestingly...

<p>In this paper, the effect of liner material of the shaped charge on jet formation and its penetration capability is investigated by experimental and numerical methods. Liner materials investigated in this paper are copper, steel, and aluminium, respectively. Pulse X-ray photographic technology to shoot the formation of jet is employed to obtain the tip velocity and the diameter of jet. A two-dimensional multi-material code is designed to simulate the entire process from jet formation to penetrating a target. A markers on cell lines method is utilised to treat the multi-material interface. The results show that aluminium jet has the highest velocity with the poorest penetration capability. Copper jet has the strongest penetration capability with a velocity higher than that of steel jet, but lower than that of aluminium jet. The simulated results agree with the experimental results very well. It also indicates that the code developed can not only address large distortion problems but also track the variation of multi-material interfaces. It is favourable to simulate the explosive loading on thin-wall structure such as shaped charge. It is proved that authors’ method is feasible and reliable for optimising the structure of shaped charge jet to dramatically improve its tip velocity and penetration capability, and provides an important theoretic basis for designing high explosive anti-tank warhead.</p><p><strong>Defence Science Journal, Vol. 65, No. 4, July 2015, pp. 279-286, DOI: http://dx.doi.org/10.14429/dsj.65.8648</strong></p>

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We report the discovery of superconductivity in pressurized CeRhGe 3 , until now the only remaining non-superconducting member of the isostructural family of non-centrosymmetric heavy-fermion compounds CeTX 3 (T = Co, Rh, Ir and X = Si, Ge). Superconductivity appears in CeRhGe 3 at a pressure of 19.6 GPa and the transition temperature T c reaches a maximum value of 1.3 K at 21.5 GPa. This finding provides an opportunity to establish systematic correlations between superconductivity and materials properties within this family. Though ambient-pressure unit-cell volumes and critical pressures for superconductivity vary substantially across the series, all family members reach a maximum T c max at a common (1.7%) critical cell volume V crit , and T c max at V crit increases with increasing spin-orbit coupling strength of the d-electrons. These correlations show that substantial Kondo hybridization and spin-orbit coupling favor superconductivity in this family, the latter reflecting the role of broken centro-symmetry.

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