A novel class of high-entropy pyrochlore compounds with multiple elements at the and B site positions (A2B2O7) was successfully obtained. Powders (La1/7Sm1/7Nd1/7Pr1/7Y1/7Gd1/7Yb1/7)2(Sn1/3Hf1/3Zr1/3)2O7 nominal composition were fabricated from pure metal oxides obtained through a reaction nitrates (for A) chlorides B) sodium hydroxide during solid-state displacement (SSDR). The phase evolution...

Pyrochlore-based glass-ceramics are attracting attention as a promising host material for immobilizing minor actinide in high-level wastes. However, the loading capacity of pyrochlore-based materials elements is to be improved, and only conventional synthetic approaches powder sintering glassy bulk crystallization were reported. Here, new (La,Y)2(Zr,Ti)2O7 subtly designed successfully prepared ...

The pyrochlore material Ho2Ti2O7 has been suggested to show "spin ice" behavior. We present neutron scattering and specific heat results that establish unambiguously that Ho2Ti2O7 exhibits spin ice correlations at low temperature. Diffuse magnetic neutron scattering is quite well described by a nearest neighbor spin ice model and very accurately described by a dipolar spin ice model. The heat c...

We study the semiclassical limit of the Sp(N) generalization of the pyrochlore lattice Heisenberg antiferromagnet by expanding about the N --> infinity saddlepoint in powers of a generalized inverse spin. To leading order, we write down an effective Hamiltonian as a series in loops on the lattice. Using this as a formula for calculating the energy of any classical ground state, we perform Monte...

We report on the study of unusual spin glass properties in the geometrically frustrated pyrochlore Tb(2)Mo(2)O(7), T(g) ~/= 24 K. The analysis of the nonlinear part of dc and complex susceptibilities, near the glass transition regime, suggests the existence of a statistical distribution of relaxation times in short-range ordered ferromagnetic clusters. In addition, the magnetic spins are not su...

Two titanium antimonate materials were tested for the removal of radiocobalt from a solution containing complexing agent EDTA to simulate a nuclear power plant decontamination solution. The first material had a mixture of pyrochlore and rutile structures and it showed high removal (91 %) of radiocobalt was removed in the presence of EDTA. The second material, which had a mopungite structure, sh...

Starting from ab initio electronic structure results we study dynamics of potassium ions in the pyrochlore superconductor KOs2O6. An effective ionic Hamiltonian characterized by an on-site instability rattler and frustrated nearest-neighbor interaction is derived and various approximations are investigated. We show that qualitative differences in the properties of KOs2O6 and its analogs RbOs2O6...

PbMg1/3Nb2/3O3 (PMN) powder was prepared by citrate organic solution, and barium titanate (BT) seed particles were added to encourage the perovskite phase formation. Sintering was followed using the constant heating rate mode of a dilatometer, and it was observed that the seed concentration affected the PMN shrinkage rate and crystal structure. The study of the lattice parameters of the samples...

Large single crystals of pyrochlore [Formula: see text] were successfully grown by the floating zone technique using an optical furnace equipped with high power xenon arc lamps. Structural investigations were carried out via powder synchrotron x-ray and neutron diffraction to establish the crystallographic structure of the materials produced. The magnetic properties of the single crystals were ...

Strongly frustrated magnetism of the metallic pyrochlore oxide Pr2Ir2O7 has been revealed by single crystal study. While Pr 4f moments have an antiferromagnetic RKKY interaction energy scale of /T*/ = 20 K mediated by Ir 5d-conduction electrons, no magnetic long-range order is found except for partial spin freezing at 120 mK. Instead, the Kondo effect, including a lnT dependence in the resistiv...