Evolution of two-step structural phase transition in Fe1+dTe detected by low-temperature x-ray diffraction

The low-temperature crystal structure of Fe1.13Te, which exhibits an anomalous two-step magnetic transition, was clarified by the systematic x-ray diffraction measurements. It was found that two-step structural phase transition, tetragonal-orthorhombic-monoclinic, occurred correspondingly to the two-step magnetic transition. The detailed analysis of the profile at 5 K indicated the coexistence of the minor orthorhombic area inside the major monoclinic lattice, which could explain the lower-shift (suppression) of the antiferromagnetic transition temperature in Fe1.13Te and suggest a possibility of superconductivity at the domain boundary.Comment: 12 pages, 3 figure

Structural and magnetic properties of Fe1+dTe single crystals

We have grown single crystals of Fe1+dTe by a conventional self-flux method. We obtained plate-like single crystals with dnom \geq 0.1. The value of the magnetization increased with increasing excess Fe concentration, and a broadening of the antiferromagnetic transition was observed for dnom >1.15. Further, we noted that the antiferromagnetic transition of Fe1.134Te (dnom = 0.15) was clearly suppressed to a lower temperature, which would indicate a possibility of controllability of magnetism by excess Fe concentration.Comment: 6 pages, 4 figures. Submitted to ISS 2011 proceedin

Superconductivity in BiS2-Based Layered Compounds

Crystal structure and physical properties of the novel BiS2-based layered superconductors are briefly reviewed. Superconductivity in the BiS2-based layered compounds is induced by electron doping into the BiS2 conduction layers. The superconducting properties seem to correlate with the crystal structure. Possible strategies for increasing transition temperature in this family are discussed.Comment: 5 pages, 3 figures, a brief review submitted to ISS2013 proceeding

Bulk superconductivity in Bi4O4S3 revealed by specific heat measurement

Specific heat experiments on a well-characterized polycrystalline sample of the BiS2 based superconductor Bi4O4S3 revealed that it shows a crear specific heat anomaly at about Tc = 4.4 K, consistent with Tc from the resistivity and dc susceptibility. This observation indicates the superconductivity of Bi4O4S3 to be bulk in nature

Poly[bis­(acetone-κO)bis­{μ3-1-[(5-chloro-2-oxidophenyl)diazenyl]-2-naphtholato-κ4 O:O,O′:O′}­sodium(I)­chromium(III)]

The title compound, [CrNa(C16H9ClN2O2)2(C3H6O)2]n, is an azo-CrIII complex polymer that is used as a charge-control agent in electrophotography. The monomeric unit is composed of octa­hedral CrIII and NaI units, and is characterized by twofold rotation symmetry. The CrIII atom is chelated by two N and four O atoms from two [(5-chloro-2-oxidophen­yl)diazen­yl]-2-naphtholate ligands. The ligand anion exists in the cis form. The NaI atom is coordinated by two phen­oxy O atoms from a neighboring CrIII unit, two naphth­oxy O atoms from another neighboring CrIII unit and two O atoms from acetone mol­ecules. The dinuclear complex forms a one-dimensional polymer running along the c axis