The pyrochlore lattice Heisenberg antiferromagnet has a massive classical ground state degeneracy. We summarize three approximation schemes, valid for large spin length S, to capture the (partial) lifting of this degeneracy when zero-point quantum fluctuations are taken into account; all three are related to analytic loop expansions. The first is harmonic order spin waves; at this order, there ...

Single nano high-entropy pyrochlore-type compound (A2B2O7) with 7 different rare-earth cations at site A and 3 metal B equiatomic amounts (7A1/7)2(3B1/3)2O7 is successfully obtained. The powder nominal composition (La1/7Sm1/7Nd1/7Pr1/7Y1/7Gd1/7Yb1/7)2(Sn1/3Hf1/3Zr1/3)2O7 was fabricated by reacting nitrates (site A) chlorides B) glycine during the combustion reaction. XRD analysis revealed that ...

Single crystals of a novel ruthenate, Ca2Ru2O7, were obtained. An X-ray diffraction study on a single crystal revealed that this material crystallizes in a pyrochlore structure with a lattice parameter, a = 10.197 Å. The magnetic susceptibility above 30 K is the summation of a Curie-Weiss contribution and a constant term independent of temperature. The effective moment per Ru atom is only 0.36 ...

The 5d transition metal oxide Cd2Os2O7 having a pyrochlore lattice of Os atoms exhibits a metal-insulator transition with a magnetic ordering at 227 K, but the magnetic structure in the ordered state and the origin of the transition have not yet been specified. The commensurate magnetic reflection with the propagation vector k = (0, 0, 0) was first observed in the resonant X-ray scattering usin...

We report on unexpected dramatic radial variations in ion tracks formed by irradiation with energetic ions (2.3 GeV (208)Pb) at a constant electronic energy-loss (~42 keV/nm) in pyrochlore-structured Gd2TiZrO7. Though previous studies have shown track formation and average track diameter measurements in the Gd2TixZr(1-x)O7 system, the present work clearly reveals the importance of the recrystal...

The thermodynamic redox properties for a series of ceria–zirconia solid solutions have been measured by determining their oxidation isotherms between 873 and 1073 K. Isotherms were obtained using Coulometric titration and using O2 titration of samples equilibrated in flowing mixtures of H2 and H2O. Samples having the following compositions were studied after calcinations at 973 and 1323 K: CeO2...

The weberite structure (A2B2X7) is an anion-deficient fluorite-related superstructure. Compared with fluorites, the reduction in the number of anions leads to a decrease in the coordination number of the B cations (VI coordination) with respect to the A cations (VIII coordination), thus allowing the accommodation of diverse cations. As a result, weberite compounds have a broad range of chemical...