Robin T. Macaluso

Discovery of the Griffiths phase in the itinerant magnetic semiconductor Fe1-xCoxS2.

Critical points that can be suppressed to zero temperature are interesting because quantum fluctuations have been shown to dramatically alter electron gas properties. Here, the metal formed by Co doping the paramagnetic insulator FeS2, Fe1-xCoxS2 is demonstrated to order ferromagnetically at x > xc = 0.01+/-0.005, where we observe unusual transport, magnetic, and thermodynamic properties. We show that this magnetic semiconductor undergoes a percolative magnetic transition with distinct similarities to the Griffiths phase, including singular behavior at xc and zero temperature.

Synthesis, structure, and magnetism of a new heavy-fermion antiferromagnet, CePdGa6

Abstract A new compound, CePdGa 6 , and its isostructural analog, LaPdGa 6 have been synthesized by flux growth and characterized by single-crystal X-ray diffraction. The compounds adopt a tetragonal structure with P 4/ mmm space group, Z =1. The lattice parameters for CePdGa 6 are a=b=4.350(3) A and c=7.922(6) A and a=b=4.3760(3) A and c=7.9230(5) A for LaPdGa 6 . Magnetic and thermal measurement have revealed that CePdGa 6 is a heavy-fermion with the specific heat coefficient γ∼300 mJ / mol K 2 and Ce f moments order antiferromagnetically along c -axis at T N =10 K . Reconfiguration of spin occurs at 5 K to induce a ferromagnetic component only in the a–b plane. This strong anisotropy in the magnetism might be related to its unique layered structure.

Synthesis, structure and dielectric characterization of Ln2Ti2−2xM2xO7(Ln=Gd, Er; M=Zr, Sn, Si)

The progress in wireless communications and information access has demanded the use of electronic ceramics exhibiting desired properties. To further our understanding of these properties, compounds in the Ln2Ti2–2xM2xO7 (Ln=Gd, Er; M=Zr, Sn, Si) systems were synthesized by ceramic methods and characterized by powder X-ray diffraction. The ZrO2–doped Gd2Ti2−2xZr2xO7 compounds adopt the pyrochlore structure type and form a complete solid solution. Er2Ti2−2xZr2xO7 forms a pyrochlore solid solution for x<0.1. However, stoichiometric Er2Zr2O7 does not form; instead Er4Zr3O12 forms a with defect fluorite structure. The Sn–doped Ln2Ti2−2xSn2xO7 (Ln=Gd, Er) compounds form complete solid solutions, and the Si compounds adopt the pyrochlore structure up to x=0.05. At ambient temperature, dielectric constants range from 10 to 61 for Er2Ti2−2xZr2xO7 and 16–31 for Gd2Ti2−2xZr2xO7 with low dielectric loss (1×10−3) at 1 GHz.

Magnetic and thermodynamic properties of cobalt-doped iron pyrite: Griffiths phase in a magnetic semiconductor

Doping of the band insulator FeS

Structures and phase transitions of CePd3+xGa8-x: new variants of the BaHg11 structure type.

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CsTe2O6–x: Novel Mixed-Valence Tellurium Oxides with Framework-Deficient Pyrochlore-Related Structure

with Co on the Fe site introduces a small density of itinerant carriers and magnetic moments. The lattice constant, AC and DC magnetic susceptibility, magnetization, and specific heat have been measured over the

Metallic Spin-Liquid Behavior of the Geometrically Frustrated Kondo Lattice Pr2Ir2O7

0\le x\le 0.085

Crystal structure and physical properties of polymorphs of LnAlB4(Ln = Yb, Lu)

range of Co concentration. The variation of the AC susceptibility with hydrostatic pressure has also been measured in a small number of our samples. All of these quantities show systematic variation with

Structure and electrical resistivity of CeNiSb3

x

Single-Crystal Growth of Ln2MIn8 (Ln = La, Ce; M = Rh, Ir): Implications for the Heavy-Fermion Ground State

including a paramagnetic to disordered ferromagnetic transition at