Physical Sciences and Mathematics Commons^™

Realization Of Random-Field Ising Ferromagnetism In A Molecular Magnet, Bo Wen, P Subedi, Lin Bo, Y Yeshurun, M P. Sarachik, A D. Kent, A J. Millis, Christos Lampropoulos, G Christou

Christos Lampropoulos

The longitudinal magnetic susceptibility of single crystals of the molecular magnet Mn12-acetate obeys a Curie-Weiss law, indicating a transition to a ferromagnetic phase at ∼0.9 K. With increasing magnetic field applied transverse to the easy axis, a marked change is observed in the temperature dependence of the susceptibility, and the suppression of ferromagnetism is considerably more rapid than predicted by mean-field theory for an ordered single crystal. Our results can instead be fit by a Hamiltonian for a random-field Ising ferromagnet in a transverse magnetic field, where the randomness derives from the intrinsic distribution of locally tilted magnetic easy axes …

Experimental Determination Of The Weiss Temperature Of Mn12-Ac And Mn12-Ac-Meoh, Christos Lampropoulos, Shiqi Li, Lin Bo, Bo Wen, M P. Sarachik, P Subedi, A D. Kent, Y Yeshurun, A J. Millis, S Mukherjee, G Christou

Christos Lampropoulos

We report measurements of the susceptibility in the temperature range from 3.5 to 6.0 K of a series of Mn12-ac and Mn12-ac-MeOH samples in the shape of rectangular prisms of length lc and square cross section of side la. The susceptibility obeys a Curie-Weiss law, χ=C/(T−θ), where θ varies systematically with sample aspect ratio. Using published demagnetization factors, we obtain θ for an infinitely long sample corresponding to intrinsic ordering temperatures Tc≈0.85 K and ≈0.74 K for Mn12-ac and Mn12-ac-MeOH, respectively. The difference in Tc for two materials that have nearly identical unit cell volumes and lattice constant ratios suggests …

Two Different One-Dimensional Structural Motifs In The Same Coordination Polymer: A Novel Interpenetration Of Infinite Ladders By Bundles Of Infinite Chains, Badruz Zaman, Mark D. Smith, Hans Conrad Zur Loye

Hans Conrad zur Loye

A coordination polymer with a novel structural motif
consisting of stacks of infinite ladders interpenetrated by
bundles of infinite chains is described; geometrical arguments
are made for the requirements that can lead to such
interpenetration as a function of ligand dimensions.

Ca4Iro6, Ca3Mgiro6 And Ca3Zniro6, Matthew J. Davis, Mark D. Smith, Hans Conrad Zur Loye

Hans Conrad zur Loye

Single crystals of tetracalcium iridium hexaoxide, Ca₄IrO₆, tricalcium magnesium iridium hexaoxide, Ca₃MgIrO₆, and tricalcium zinc iridium hexaoxide, Ca₃ZnIrO₆, were prepared via high-temperature flux growth and structurally characterized by single-crystal X-ray diffraction. The three compounds are isostructural and adopt the K₄CdCl₆ structure type, comprised of chains of alternating face-shared [CaO₆], [MgO₆] or [ZnO₆] trigonal prisms and [IrO₆] octahedra, surrounded by columns of Ca²⁺ ions.

Formula: Ca₄IrO₆, Ca_3.34Mg_0.66IrO₆ and …

Structure Determination Of Ba8Corh6O21, A New Member Of The 2h-Perovskite Related Oxides, Hans Conrad Zur Loye, M. D. Smith, K. E. Stitzer, A. El Abed, J. Darriet

Hans Conrad zur Loye

Single crystals of Ba₈CoRh₆O₂₁ were grown out of a potassium carbonate flux. The structure was solved by a general method using the superspace group approach. The superspace group employed was R3m(00γ)0s with a = 10.0431(1) Å, c₁ = 2.5946(1) Å and c₂ = 4.5405(1) Å, V = 226.60(1) ų. Ba₈CoRh₆O₂₁ represents the first example of an m = 5, n = 3 member of the A_3n+3mA'_nB_3m+nO_9m+6n family of 2H hexagonal perovskite related oxides and contains chains consisting of six …

Sr3Znpto6 And Sr3Cdpto6, Mark D. Smith, Hans Conrad Zur Loye

Hans Conrad zur Loye

The flux synthesis of single crystals of the isostructural compounds tristrontium zinc platinum hexaoxide, Sr₃ZnPtO₆, and tristrontium cadmium platinum hexaoxide, Sr₃CdPtO₆, is reported. The compounds adopt the pseudo-one-dimensional rhombohedral K₄CdCl₆ structure type, and feature chains of face-shared distorted ZnO₆ or CdO₆ trigonal prisms and PtO₆ octahedra, surrounded by columns of Sr²⁺ ions. All transition metals are located on the threefold axis of symmetry, while the Sr²⁺ cations lie on twofold axes.

Formula: Sr₃ZnPtO₆ and Sr₃CdPtO₆

Three Unique Coordination Geometries Involving 1,2-Dimethoxy-4,5-Bis(2-Pyridylethynyl)Benzene, Jeffrey E. Fiscus, Sandra Shotwell, Ralph C. Layland, Mark D. Smith, Hans Conrad Zur Loye, Uwe H. F. Bunz

Hans Conrad zur Loye

Reaction of the new ligand 1,2-dimethoxy-4,5-bis(2-pyridylethynyl) benzene with different metal centers under similar reaction conditions led to three distinct structure formation processes: molecular ring closure, dimerization, and polymer formation.

Catena-Poly[[Bis(Α-Thenoyltrifluoroacetonato)Copper(Ii)]-Μ-1,4-Di-4-Pyridyl-2,3-Diazabuta-1,3-Diene], William J. Perkins, Tamara Maxwell, Mark D. Smith, Leroy Peterson Jr., Hans Conrad Zur Loye

Hans Conrad zur Loye

In the one-dimensional title polymer, [Cu(C₈H₄F₃O₂S)₂(C₁₂H₁₀N₄)]_n or [Cu(L)₂(tta)₂] [tta is -thenoyltrifluoroacetonato and L is 1,4-bis(4-pyridyl)-2,3-diaza-1,3-butadiene], Cu²⁺ lies on a center of inversion. It is axially coordinated by two pyridyl N atoms from two different L ligands and equatorially coordinated by four O atoms from two chelating tta ligands. The ligand L propagates the one-dimensional chain structure by serving as a bridging ligand between two Cu octahedra via Cu-N coordinate bonds.

Sm2Nairo6, A Monoclinically Distorted Double Perovskite, Samuel J. Mugavero Iii, Irina V. Puzdrjakova, Mark D. Smith, Hans Conrad Zur Loye

Hans Conrad zur Loye

Single crystals of the lanthanide-containing iridate, disamarium sodium iridium hexaoxide, Sm₂NaIrO₆, were prepared via high-temperature flux growth and structurally characterized by single-crystal X-ray diffraction. The compound crystallizes in the monoclinic space group P2₁/n and is a double perovskite, consisting of a 1:1 ordered rock-salt-type lattice of corner-shared NaO₆ and IrO₆ distorted octahedra. Samarium occupies the eightfold coordination site generated by the connectivity of the octahedra.

Diaquabis(5-Fluoro-2-Hydroxybenzoato-Κo1)Zinc(Ii), Diana Rishmawi, Jennifer Kelley, Mark D. Smith, Leroy Peterson, Hans Conrad Zur Loye

Hans Conrad zur Loye

The title compound, [Zn(C₇H₄FO₃)₂(H₂O)₂], is a monomeric Zn^II complex. The Zn^II atom, which lies on a twofold rotation axis, is situated in a distorted tetrahedral environment composed of two monodentate carboxlyate O atoms and two water O atoms. O-HO hydrogen bonds link these units, forming sheets that are stacked along the c axis.

Catena-Poly[[Bis(Α-Thenoyltrifluoroacetonato-Κ2O,O')Copper(Ii)]-Μ-1,4-Di-3-Pyridyl-2,3-Diaza-1,3-Butadiene-Κ2N:N'], William J. Perkins, Tamar Maxwell, Ken B. Williams, Andrea M. Goforth, Mark D. Smith, Leroy Peterson Jr., Hans Conrad Zur Loye

Hans Conrad zur Loye

The title compound, [Cu(C₈H₄F₃O₂S)₂(C₁₂H₁₀N₄)]_n or [Cu(tta)₂(L2)₂]_n (L2 = 1,4-di-3-pyridyl-2,3-diaza-1,3-butadiene and tta = -thenoyltrifluoroacetonate), consists of undulating chains containing two crystallographically distinct Cu^II centers that are each located on inversion centers. Each Cu^II center exhibits distorted octahedral coordination provided by two pyridyl N atoms from two equivalent L2 ligands and four O atoms from two equivalent tta ligands. The chains interact through weak C-FH-C contacts.

Crystal Growth, Structure Determination And Magnetism Of A New Hexagonal Rhodate: Ba9rh8o24, Katharine E. Stitzer, M. D. Smith, J. Darriet, Hans Conrad Zur Loye

Hans Conrad zur Loye

Single crystals of Ba9Rh8O24, grown from a molten potassium carbonate flux, crystallize in the spacegroup R¯3c with lattice parameters of a = 10.0899(4) and c = 41.462(2) Å. Magnetic measurements on oriented single crystals reveal the existence of magnetic anisotropy

Poly[[(Μ-2,2'-Bipyrimidine-Κ4N1,N1':N3,N3')(Μ-Sulfato-Κ2O:O')Zinc(Ii)] Monohydrate], Aaron Oxendine, Jennifer Kelley, Leroy Peterson Jr., Mark D. Smith, Hans Conrad Zur Loye

Hans Conrad zur Loye

In the title compound, {[Zn(SO4)(C8H6N4)]·H2O}n, the ZnII atom is in a distorted octahedral environment. The ZnII atoms are bridged by both 2,2'-bipyrimidine and sulfate ligands, thus forming a three-dimensional polymeric metal-organic solid that contains uncoordinated water molecules in the interstitial space. O-HO hydrogen bonding consolidates the crystal structure.