Magnetic diversity in three-dimensional two-fold-interpenetrated structures: a story of two compounds.

A magnetostructural correlation has been carried out for two newly synthesized two-fold-interpenetrated three-dimensional structures. Compound 1, denoted as [Ni(L1)(L2)]·2DMF (where L1 is 1,4-benzene-dicarboxylic acid (BDC), L2 is 4,4-oxybis-(N-(pyridine-4-yl)benzamide), and DMF is N,N'-dimethylformamide), was observed to have a three-dimensional structure with two-fold interpenetration. Compound 2, denoted as [Co(L3)(L2)]·2DMF (where L3 is 2,5-thiopehene-dicarboxylic acid (TDC)), was also observed to display a three-dimensional structure with an architecture identical to that of compound 1. Both compounds were well characterised using several techniques including single-crystal X-ray diffraction, powder X-ray diffraction, TGA, and IR. Magnetism and specific heat measurements of compound 1 revealed a canted-antiferromagnetic transition at TN ≈ 4 K and a field-induced spin-flop transition at a relatively low field strength. These exotic features were attributed to the low-symmetry space group P(1[combining macron]) and single-ion anisotropy of the Ni2+ sub-lattice. In contrast, compound 2 was found to be weakly antiferromagnetic in nature with a negligible interaction between the magnetic Co2+ ions.

Structural and magnetic properties of spin-1/2 dimer compound Cu2(IPA)2(DMF)(H2O) with a large spin gap.

We present the synthesis and a detailed investigation of structural and magnetic properties of metal-organic compound Cu2(IPA)2(DMF)(H2O) by means of x-ray diffraction, magnetization, and heat capacity measurements. Single crystals of the title compound were synthesized by judicious selection of organic ligand and employing a selective hydrothermal reaction route. It crystallizes in an orthorhombic structure with space group Cmca. The structural analysis revealed that two Cu2+ ions are held together by the organic component (-O-C-O-) in a square paddle-wheel to form spin dimers which are aligned perpendicular to each other and are further coupled through organic ligands (isophthalic acid) forming two-dimensional layers. Temperature dependent magnetic susceptibility [Formula: see text] could be described well using spin-1/2 dimer model. The spin susceptibility [Formula: see text] shows an exponential decrease in the low temperature region, below the broad maximum, confirming the singlet ground state with a large spin gap of [Formula: see text] K. The heat capacity C p measured as a function of temperature also confirms the absence of magnetic long-range-order down to 2 K.

Double phase transition in the triangular antiferromagnet Ba3CoTa2O9.

Here, we report the synthesis and magnetic properties of a new triangular lattice antiferromagnet Ba3CoTa2O9. The effective spin of Co2+ is found to be J = 1/2 at low temperatures due to the combined effect of crystal field and spin-orbit coupling. Ba3CoTa2O9 undergoes two successive magnetic phase transitions at [Formula: see text] K and [Formula: see text] K in zero applied field, which is typical for triangular antiferromagnets with the easy-axis magnetic anisotropy. With increasing field, the transition anomalies are found to shift toward low temperatures, confirming the antiferromagnetic nature of the transitions. At higher fields, the transition peaks in the heat capacity data disappear and give way to a broad maximum, which can be ascribed to a Schottky anomaly due to the Zeeman splitting of spin levels. The H - T phase diagram of the compound shows three distinct phases. The possible nature of these phases is discussed.

Assessment of the accuracy and reliability of new 3-dimensional scanning devices.

INTRODUCTION: The primary objective of this study was to assess the accuracy and the reliability of the SureSmile OraScanner (Orametrix, Richardson, Tex) by comparing it with other desktop 3-dimensional scanners: VIVID910 (Konica Minolta, Tokyo, Japan) and R700 (3Shape, Copenhagen, Denmark). A laser-based scanner, the SLP250 Laser Probe (Laser Design, Detroit, Mich), served as the gold standard. METHODS: Five sets of dental casts were used. First, the accuracy of each scanner was studied by comparing the 3-dimensional models created by OraScanner, VIVID910, and R700 with the gold standard 3-dimensional models of the SLP250. To assess the reliability of the 3-dimensional models, the shell/shell deviation of each model was calculated based on the same surface-based registrations for all 5 sets of dental casts. RESULTS: OraScanner, VIVID910, and R700 were sufficiently accurate when compared with the gold standard. In the assessment of reliability, there were no significant differences between all comparisons. CONCLUSIONS: The results showed that the OraScanner system has a sophisticated algorithm for 3-dimensional surface registration and can be used to generate accurate and reliable 3-dimensional digital models for use by clinicians.