GdPtPb: A noncollinear antiferromagnet with distorted kagome lattice

In the spirit of searching for Gd-based, frustrated, rare earth magnets, we have found antiferomagnetism (AF) in GdPtPb, which crystallizes in the ZrNiAl-type structure that has a distorted kagome lattice of Gd triangles. Single crystals were grown and investigated using structural, magnetic, transport, and thermodynamic measurements. GdPtPb orders antiferromagnetically at 15.5 K, arguably with a planar, noncollinear structure. The high temperature magnetic susceptibility data reveal an “anti-frustration” behavior having a frustration parameter, |f|=|Θ|/TN=0.25, which can be explained by mean field theory within a two-sublattice model. Study of the magnetic phase diagram down to T=1.8K reveals a change of magnetic structure through a metamagnetic transition at around 20 kOe and the disappearance of the AF ordering near 140 kOe. In total, our work indicates that GdPtPb can serve as an example of a planar, noncollinear AF with a distorted kagome magnetic sublattice

Isotope effect on electron-phonon interaction in the multiband superconductor MgB2

We investigate the effect of isotope substitution on the electron-phonon interaction in the multiband superconductor MgB2 using tunable laser-based angle-resolved photoemission spectroscopy. The kink structure around 70 meV in the σ band, which is caused by electron coupling to the E2g phonon mode, is shifted to higher binding energy by ∼3.5 meV in Mg10B2 and the shift is not affected by superconducting transition. These results serve as the benchmark for investigations of isotope effects in known, unconventional superconductors and newly discovered superconductors where the origin of pairing is unknown

Growth and characterization of BaZnGa

We report the growth, structure and characterization of BaZnGa, identifying it as the sole known ternary compound in the Ba-Zn-Ga system. Single crystals of BaZnGa can be grown out of excess Ba-Zn and adopt a tI36 structure type. There are three unique Ba sites and three M\,=\,Zn/Ga sites. Using DFT calculations we can argue that whereas one of these three M sites is probably solely occupied by Ga, the other two M sites, most likely, have mixed Zn/Ga occupancy. Temperature dependent resistivity and magnetization measurements suggest that BaZnGa is a poor metal with no electronic or magnetic phase transitions between 2\,K and 300\,K

Observation of superconductivity in the noncentrosymmetric nodal chain semimetal Ba5In4Bi5

The combination with superconductivity and topological nontrivial band structure provides a promising route towards novel quantum states such as topological superconductivity. Here, we report the first observation of superconductivity (4.1 K) in Ba5In4Bi5 single crystal, a noncentrosymmetric topological semimetal featuring nodal chain loops at the high-symmetry points R and X. The magnetization, resistivity, and specific heat capacity measurements reveal that Ba5In4Bi5 is a moderately coupled type-II Bardeen-Cooper-Schrieffer superconductor. Bulk superconductivity is suggested from the magnetic susceptibility and specific heat measurements. The results show that Ba5In4Bi5 provides a new platform for exploring the relationship of superconductivity and topological nontrivial band topology

Effect of pressure on the physical properties of the superconductor NiBi3

Here, we present an experimental study of the superconducting properties of NiBi 3 as a function of pressure by means of resistivity and magnetization measurements and combine our results with DFT calculations of the band structure under pressure. We find a moderate suppression of the critical temperature T c from ~ 4.1 K to ~ 3 K by pressures up to 2 GPa. By taking into account the change of the band structure as a function of pressure, we argue that the decrease in T c is consistent with conventional, electron-phonon-mediated BCS-type superconductivity

GdPtPb: A noncollinear antiferromagnet with distorted kagome lattice

In the spirit of searching for Gd-based, frustrated, rare earth magnets, we have found antiferomagnetism (AF) in GdPtPb, which crystallizes in the ZrNiAl-type structure that has a distorted kagome lattice of Gd triangles. Single crystals were grown and investigated using structural, magnetic, transport, and thermodynamic measurements. GdPtPb orders antiferromagnetically at 15.5 K, arguably with a planar, noncollinear structure. The high temperature magnetic susceptibility data reveal an “anti-frustration” behavior having a frustration parameter, |f|=|Θ|/TN=0.25, which can be explained by mean field theory within a two-sublattice model. Study of the magnetic phase diagram down to T=1.8K reveals a change of magnetic structure through a metamagnetic transition at around 20 kOe and the disappearance of the AF ordering near 140 kOe. In total, our work indicates that GdPtPb can serve as an example of a planar, noncollinear AF with a distorted kagome magnetic sublattice.This article is published as Manni, S., Sergey L. Bud'ko, and Paul C. Canfield. "GdPtPb: A noncollinear antiferromagnet with distorted kagome lattice." Physical Review B 96, no. 5 (2017): 054435. DOI: 10.1103/PhysRevB.96.054435. Posted with permission.</p

Effect of pressure on the physical properties of the superconductor NiBi3

Here, we present an experimental study of the superconducting properties of NiBi 3 as a function of pressure by means of resistivity and magnetization measurements and combine our results with DFT calculations of the band structure under pressure. We find a moderate suppression of the critical temperature T c from ~ 4.1 K to ~ 3 K by pressures up to 2 GPa. By taking into account the change of the band structure as a function of pressure, we argue that the decrease in T c is consistent with conventional, electron-phonon-mediated BCS-type superconductivity.</p