Dipolar magnetic order in the pyrochlore structure

We present a detailed theoretical overview of the thermodynamic properties of the dipolar spin ice model, which has been shown to be an excellent quantitative descriptor of the Ising pyrochlore materials Dy2Ti2O7 and Ho2Ti2O7. We show that the dipolar spin ice model can reproduce an effective quasi macroscopically degenerate ground state and spin-ice behavior of these materials when the long-range nature of dipole-dipole interaction is handled carefully using Ewald summation techniques. This degeneracy is, however, ultimately lifted at low temperature. The long-range ordered state is identified via mean field theory and Monte Carlo simulation techniques. Finally, we investigate the behavior of the dipolar spin ice model in an applied magnetic field, and compare our predictions with experimental results. We find that a number of different long-range ordered states are favored by the model depending on field direction.

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“…J nn /D nn = −0.905, in agreement with the results found in mean field [52,53] and exact [85] calculations.…”

Section: Discussionsupporting

confidence: 89%

Monte Carlo studies of the dipolar spin ice model

Melko¹,

Gingras²

2004

J. Phys.: Condens. Matter

211

354

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“…Tetravalent cerium has a very similar ionic radius to tetravalent plutonium (for a given coordination number) making it a good surrogate from a crystallographic viewpoint [8]. This solid solution and related rare earth oxide pyrochlores, is also of interest for application as a solid electrolyte in solid oxide fuel cells [9][10][11].…”

Section: Introductionmentioning

confidence: 99%

The fluorite related modulated structures of the Gd2(Zr2−xCex)O7 solid solution: An analogue for Pu disposition

Reid

Stennett

Hyatt

2012

Journal of Solid State Chemistry

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“…The pyrochlore structure type has great many uses, examples of which include magnetic materials [1,2], oxide fast ion conductors [3][4][5][6], and matrices for immobilisation of highly active radionuclides from nuclear wastes [7][8][9][10]. The last two applications are currently of major interest, as in both cases pyrochlores are capable of overcoming many technological problems, whilst remaining cost effective.…”

Section: Introductionmentioning

confidence: 99%

Lanthanum pyrochlores and the effect of yttrium addition in the systems La2−xYxZr2O7 and La2−xYxHf2O7

Whittle

Cranswick

Redfern

et al. 2009

Journal of Solid State Chemistry

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The crystal structures of the compounds La 2Àx Y x Zr 2 O 7 and La 2Àx Y x Hf 2 O 7 with x ¼ 0.0, 0.4, 0.8, 1.2, 1.6, and 2.0 have been studied using neutron powder diffraction and electron microscopy to determine the stability fields of the pyrochlore and fluorite solid solutions. The limits of pyrochlore stability in these solid solutions are found to be close to La 0.8 Y 1.2 Zr 2 O 7 and La 0.4 Y 1.6 Hf 2 O 7 , respectively. In both systems the unit cell parameter is found to vary linearly with Y content across those compositions where the pyrochlore phase is stable, as does the x-coordinate of the oxygen atoms on the 48f (x, 3 8 , 3 8 ) sites. In both systems, linear extrapolations of the pyrochlore data suggest that the disordering is accompanied by a small decrease in the lattice parameter of approximately 0.4%. After the pyrochlore solid solution limit is reached, a sharp change is observed from x$0.41 to 0.375 as the disordered defect fluorite structure is favoured. Electron diffraction patterns illustrate that some short-range order remains in the disordered defect fluorite phases.

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Dipolar magnetic order in the pyrochlore structure

Cited by 12 publications

References 16 publications

Monte Carlo studies of the dipolar spin ice model

Monte Carlo studies of the dipolar spin ice model

The fluorite related modulated structures of the Gd2(Zr2−xCex)O7 solid solution: An analogue for Pu disposition

Lanthanum pyrochlores and the effect of yttrium addition in the systems La2−xYxZr2O7 and La2−xYxHf2O7

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