Frustration and Glasslike Character in RInMn O (R = Tb, Dy, Gd).

We bring together ac susceptibility and dc magnetization to uncover the rich magnetic field-temperature behavior of a series of rare earth indium oxides, RInO (R = Tb, Dy, and Gd). The degree of frustration is much larger than expected, particularly in TbInO, and the ground states are glasslike with antiferromagnetic tendencies. The activation energy for spin reorientation is low.

Doped SrFeIrO-Phase Separation and a J ≠ 0 State for Ir.

High-resolution synchrotron X-ray and neutron powder diffraction data demonstrate that, in contrast to recent reports, SrFeIrO adopts an I1̅ symmetry double perovskite structure with an abc tilting distortion. This distorted structure does not tolerate cation substitution, with low levels of A-site (Ca, Ba, La) or Fe-site (Ga) substitution leading to separation into two phases: a stoichiometric I1̅ phase and a cation-substituted, P2/ n symmetry, aac distorted double perovskite phase. Magnetization, neutron diffraction, and Fe Mössbauer data show that, in common with SrFeIrO, the cation substituted SrA FeGa IrO phases undergo transitions to type-II antiferromagnetically ordered states at T ∼ 120 K.

Implications of bond disorder in a S=1 kagome lattice.

Strong hydrogen bonds such as F···H···F offer new strategies to fabricate molecular architectures exhibiting novel structures and properties. Along these lines and, to potentially realize hydrogen-bond mediated superexchange interactions in a frustrated material, we synthesized [HF][NiF(Fpy)][SbF] (Fpy = 3-fluoropyridine). It was found that positionally-disordered HF ions link neutral NiF(Fpy) moieties into a kagome lattice with perfect 3-fold rotational symmetry.

The Parent Li(OH)FeSe Phase of Lithium Iron Hydroxide Selenide Superconductors.

Lithiation of hydrothermally synthesized LiFe(OH)FeSe turns on high-temperature superconductivity when iron ions are displaced from the hydroxide layers by reductive lithiation to fill the vacancies in the iron selenide layers. Further lithiation results in reductive iron extrusion from the hydroxide layers, which turns off superconductivity again as the stoichiometric composition Li(OH)FeSe is approached. The results demonstrate the twin requirements of stoichiometric FeSe layers and reduction of Fe below the +2 oxidation state as found in several iron selenide superconductors.

Octanuclear Heterobimetallic {Ni4Ln4} Assemblies Possessing Ln4 Square Grid [2 × 2] Motifs: Synthesis, Structure, and Magnetism.

Octanuclear heterobimetallic complexes, [Ln4Ni4(H3L)4(μ3-OH)4(μ2-OH)4]4Cl·xH2O·yCHCl3 (Dy(3+), x = 30.6, y = 2 (1); Tb(3+), x = 28, y = 0 (2) ; Gd(3+), x = 25.3, y = 0 (3); Ho(3+), x = 30.

Heterometallic trinuclear {CoLn(III)} (Ln = Gd, Tb, Ho and Er) complexes in a bent geometry. Field-induced single-ion magnetic behavior of the Er(III) and Tb(III) analogues.

Through the use of a multi-site compartmental ligand, 2-methoxy-6-[{2-(2-hydroxyethylamino)ethylimino}methyl]phenol (LH3), the family of heterometallic, trinuclear complexes of the formula [CoLn(L)2(μ-O2CCH3)2(H2O)3]·NO3·xMeOH·yH2O has been expanded beyond Ln = Dy(III) to include Gd(III) (), Tb(III) (), Ho(III) () and Er(III) () for , and (x = 1; y = 1) and for (x = 0; y = 2). The metallic core of these complexes consists of a (Co(III)-Ln(III)-Co(III)) motif bridged in a bent geometry resulting in six-coordinated distorted Co(III) octahedra and nine-coordinated Ln(III) monocapped square-antiprisms. The magnetic characterization of these compounds reveals the erbium and terbium analogues to display a field induced single-ion magnetic behavior similar to the dysprosium analogue but at lower temperatures.

Synthesis and properties of lanthanide ruthenium(III) oxide perovskites.

An extensive series of new LnRuO3 perovskites has been synthesized at high pressure. These ruthenium(III)-based oxides are ruthenium deficient, and high-pressure samples have compositions close to LnRu(0.9)O3.

Quantifying magnetic exchange in doubly-bridged Cu-X(2)-Cu (X = F, Cl, Br) chains enabled by solid state synthesis of CuF(2)(pyrazine).

Solid state techniques involving pressure and temperature have been used to synthesize the fluoride member of the CuX(2)(pyrazine) (X = F, Cl, Br) family of coordination polymers that cannot be crystallized by solution methods. CuF(2)(pyrazine) exhibits unique trans doubly-bridged Cu-F(2)-Cu chains that provide an opportunity to quantify magnetic superexchange in an isostructural Cu-X(2)-Cu series.