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Highlights • Mn 3 Fe 2 Si 3 O 12 orders antiferromagnetically with a garnet structure. • A related glassy phase is magnetically frustrated and a spin glass. • The composition of the glassy phase is Mn 3 Fe 2 Si 3 O 13. Abstract The crystalline garnet Mn 3 Fe 2 Si 3 O 12 and an amorphous phase of the same nominal composition are synthesized at high pressure. The magnetic properties of the two forms are reported. Both phases order antiferromagnetically. The crystalline phase exhibits a Curie-Weiss theta of −37.2 K, with a sharp ordering transition at 12 K. The glassy phase exhibits a larger antiferromagnetic Curie-Weiss theta, of −89.7 K, with a broad ordering transition observed at 2.5 K. The amorphous phase shows a much higher degree of magnetic frustration than the crystalline phase; it exhibits spin-glass behavior and is determined to have an actual composition of Mn 3 Fe 2 Si 3 O 13. [ABSTRACT FROM AUTHOR]

Graphical abstract The system is magnetically disturbed by a substantial amount of Ti/Ru chemical disorder. The Weiss temperature and effective magnetic moment were found to be −29.5 K and 1.82 μ B /f.u. respectively, and a bifurcation in the zero field cooled and field cooled magnetic susceptibility is observed below 4.7 K, suggesting that Ba 3 TiRu 2 O 9 is a compositionally-disordered spin-glass system. Abstract The magnetic properties of Ba 3 TiRu 2 O 9 , whose crystal structure is based on stacked triangular planar lattices of M 2 O 9 dimers and single MO 6 octahedra, are reported. The system is magnetically disturbed by a substantial amount of Ti/Ru chemical disorder. The Weiss temperature and effective magnetic moment were found to be −29.5 K and 1.82 μ B /f.u. respectively, and a bifurcation in the zero field cooled and field cooled magnetic susceptibility is observed below 4.7 K, suggesting that this is a compositionally-disordered spin-glass system. The material is a semiconductor with an activation energy for charge transport of approximately 0.14 eV. [ABSTRACT FROM AUTHOR]

Abstract: The low temperature thermoelectric properties of TiSe2, co-doped with Cu and S, are reported. Partial S substitution for Se changes the magnitude of the indirect bandgap, while the Cu-doping independently controls the n-type carrier concentration. The Seebeck coefficients are negative, in the range of −50 to −200μVK−1, and the resistivities are 0.1–10mΩcm. The thermal conductivity for the sample with the largest thermoelectric power factor was found to be relatively low, 3–4Wm−1 K−1, and decreases with decreasing temperature. The thermoelectric efficiencies for the best materials found in this system, typified by Cu0.02TiSe1.7S0.3, were largest at 0.07 at 300K and decreased to 0.01 at 75K. [Copyright &y& Elsevier]

The magnetic properties of transparent pink Na 2 Mn 3 Cl 8 and NaMnCl 3 are presented. For both phases, the effective magnetic moments are large, while the Curie-Weiss thetas are below 10 K. The compounds crystallize in the trigonal R -3 m and R -3 space groups, respectively. A Kagome plane of Mn2+ octahedrally coordinated to Cl− is found in Na 2 Mn 3 Cl 8 and the material has no apparent magnetic ordering above 1.8 K, while the octahedrally coordinated, honeycomb network of Mn2+ in NaMnCl 3 orders antiferromagnetically at 6.3 ± 0.2 K. The heat capacity of NaMnCl 3 has one transition, consistent with the susceptibility, while Na 2 Mn 3 Cl 8 exhibits a more complex heat capacity with two peaks, at 0.6 K and 1.4 K. A third, broad peak near 6.2 K in the heat capacity of Na 2 Mn 3 Cl 8 is problematic but may be due to the intergrowth of NaMnCl 3 domains. [ABSTRACT FROM AUTHOR]

Abstract: The dielectric constant in many insulating magnets exhibits pronounced changes at magnetic ordering temperatures or with the application of external magnetic fields. As the dielectric response is sensitive to materials properties at non-zero wavevectors, dielectric spectroscopy provides additional insight into spin structures in these insulators beyond what can be determined using bulk magnetization measurements alone. We present illustrative examples of intrinsic magnetodielectric coupling in non-polar ferro- and antiferromagnets, SeCuO3 and TeCuO3 respectively, and of magnetodielectric coupling in a polar system, specifically Ni3V2O8. We also show an example of how spurious magnetocapacitive effects can significantly modify the magnetodielectric response of a system. We include with some general comments on how the magnetodielectrics may be useful for device applications and how the coupling may be enhanced by modifying the materials. [Copyright &y& Elsevier]

Abstract: The mixed anion skutterudite IrSn1.5Te1.5 has been synthesized and characterized by X-ray powder diffraction, thermopower and electrical resistivity measurements. Structural analysis reveals that Sn and Te order in layers perpendicular to the [111] direction of the skutterudite unit cell, and a distortion of the anion sublattice is evident. The thermopower is 160 μV/K at room temperature, while the electrical resistivity is . The effects of chemical substitutions on the Ir site (Ru, Pd) and Sn site (In, Sb) have been investigated. The power factor was found to improve with In substitution but, at 0.9 μW/K2 cm, is too small for this material to be useful for thermoelectric applications. [Copyright &y& Elsevier]

We report the effects of partial substitutions of the VIIIa elements: Fe (3d) and Ru (4d) in the intermetallic perovskite superconductor MgCNi3. In both the MgCNi3-xRux and MgCNi3-xFex systems, the superconducting critical temperature (TC) decreases monotonically as x is increased. TC decreases more slowly in the case of Ru, suggesting that the 3d electrons in Fe are magnetically pair breaking. This is supported by the normal state magnetic susceptibility measurements (χ), which shows that χ increases with Fe and decreases with Ru doping. No ferromagnetism is observed in either system. [Copyright &y& Elsevier]

Partial substitution of boron for phosphorus in the ternary phosphide superconductors ZrRuP and LaRu2P2 induces highly anisotropic structural changes and suppresses the superconducting transition temperatures. Undoped ZrRuP [hexagonal, a=6.445(4) Å, c=3.765(2) Å] systematically expands for ZrRuP1-xBx (x=0.05, 0.10, 0.15, 0.20, 0.40) in the a direction to 6.949(4) Å and shrinks in the c direction to 3.601(3) Å. Superconductivity is still present in the boron-substituted samples, although Tc drops from 10.1 K in ZrRuP to 5.6 K in ZrRuP0.6B0.4. LaRu2P2 [tetragonal, a=4.032(2) Å, c=10.632(7) Å] remains essentially unchanged along the a axis [a=4.037(1) Å] upon substitution at a starting composition of LaRu2P1.6B0.4, but shrinks along the c axis to 10.477(5) Å. Accordingly, the superconducting Tc drops from 4.0 K for LaRu2P2 to 2.0 K for LaRu2P1.6B0.4. [Copyright &y& Elsevier]