Radiation-induced amorphization of rare-earth titanate pyrochlores

Prediction of Irradiation Spectrum Effects in Pyrochlores

“…This is a consequence of the fact that, as compared to the Zr or Hf families of pyrochlores, which display nearly linear trends in the disordering energies as a function of the A 3+ cation radius, the titanate family exhibits a more complex behavior. As noted above, the titanate disordering energy is non-monotonic with A 3+ cation radius, peaking at A=Gd, in accordance with experimental results 8 .…”

“…For example, both types of calculations show a peak in the titanate family of pyrochlores at Gd 2 Ti 2 O 7 , consistent with experimental measurements of the critical temperature for amorphization 8 . Further, both DFT and empirical potentials show that the energetics of the reactions represented in Eqs.…”

Static magnetic susceptibility, crystal field and exchange interactions in rare earth titanate pyrochlores

“…The pyrochlore lattice has a rhombohedral primitive unit cell with translation vectors a 1 = a(1/2 1/2 0), a 2 = a(1/2 0 1/2), a 3 = a(0 1/2 1/2) and contains four magnetically nonequivalent face-centered R-sublattices with the basis vectors r 1 = a(111)/8, r 2 = a(11 1)/8, r 3 = a(1 11)/8 and r 4 = a(111)/8, where a is the lattice constant which varies approximately linearly with the ionic radius of the R-ion (at room temperature a = 1.020 56 nm (R = Sm); a = 1.003 25 nm (R = Yb)) [1]. The point symmetry group at the R-site is D 3d , the trigonal symmetry axis is oriented along the corresponding basis vector.…”

“…The pyrochlore lattice belongs to the class of geometrically frustrated systems where interactions between magnetic ions cannot be minimized simultaneously. The rare earth titanates R 2 Ti 2 O 7 with the cubic Fd3m space group have such an arrangement of rare earth ions, R 3+ [1], and, as a consequence of the geometric frustration, exhibit a large variety of intriguing equilibrium and dynamic magnetic properties (for a review see [2] 7 have been discovered so far. To better understand these exotic magnetic properties, i.e.…”

Influence of thermally induced oxygen order on mobile ion dynamics inGd2(Ti0.65Zr0.35)2Moreno1, Fuentes2, Mączka3 et al. 2007Phys. Rev. B445190View full textAdd to dashboardCite

“…9 Mechanical milling allows preparing partially disordered and metastable RE 2 Ti 2 O 7 pyrochlores, 10 obtained otherwise only by chemical substitution, ion irradiation, or pressureinduced compression. 9,11,12 We have reported in a previous work on the influence of chemically induced disorder ͑Zr substitution for Ti͒ in oxygen dynamics, and consequently on the electrical properties, of the Gd 2 ͑Ti 1−y Zr y ͒ 2 O 7 series. 13 In this work, we will present the evolution of the structural disorder in metastable Gd 2 ͑Ti 0.65 Zr 0.35 ͒ 2 O 7 powders prepared by mechanical milling with postmilling thermal treatments.…”