The mechanism behind the observed sample dependency in the heavy-fermion superconductor UBe13 was attributed to the presence of Al impurities in single-crystals. Various diffraction and spectroscopy techniques as well as transmission electron microscopy revealed the location of Al in the structure and its influence on the superconducting properties. Upon long-term annealing, Al atoms can leave the crystal and restore the properties of Al-free UBe13.
A thorough experimental characterization with a theoretical analysis of the chemical bonding of the intermetallic compound MnSiPt leads to surprising results: the formation of direct Mn–Mn bonds is suppressed because the energy gain due to bond formation is significantly smaller than the on-site magnetic interactions. Therefore, after formation of the covalent bonds between Pt and Si as well as between Mn and Si, the strong Mn intra-atomic exchange is the key factor for the stability of the crystal structure. In competition against the Mn–Mn bond formation, intra-atomic magnetic interactions determine the topology of the local atomic arrangement in the finally adopted TiNiSi-type crystal structure in MnSiPt.
A combination of scanning tunneling microscopy and locally resolved magnetic stray field measurements unambiguously revealed the polaron formation in the ferromagnetic semimetal EuB6. These polarons are at the heart of the colossal magnetoresistive effects near the ferromagnetic transition in this material.
On Saturday, 23 June 2018, the Dresden Dragonboat Festival occurred for the 27th time. More than 80 “dragon”-teams – among them our team PLANCKTON consisting of 19 members and guests of MPI CPfS – showed great strength, endurance and skill in compete for the highly coveted trophies.[more]
The new Mn–rich alkaline earth nitridomanganates Ca12[Mn19N23] and Ca133[Mn216N260] represent the first examples of layered nitridomanganates and possess crystal structures with extended 2D networks of chemically bonded Mn atoms. They contain similar building blocks but of different levels of structural complexity. Furthermore, Ca133[Mn216N266] is the first representative of complex intermetallic structures with preferably covalent (two- and four-centre) bonding.
The first heavy-fermion superconductor CeCu2Si2 was thought to have d-wave gap with node, until recent new measurements evident a fully opened gap. Recently, scientists from MPI-CPfS, Zhejiang University, Rice University and the University of Augsburg found a resolution to this puzzle based on measurements of the London penetration depth, which reconcile the d-wave pairing symmetry and nodeless gap structure.