Magnetic pyrochlore oxides

Gardner, J. S.; Gingras, Michel J. P.; Greedan, John E.

doi:10.1103/revmodphys.82.53

Cited by 1,345 publications

(1,431 citation statements)

References 352 publications

Supporting

Mentioning

1,365

Contrasting

Unclassified

Order By: Relevance

“…This is a very remarkable result, which also indicates that the holographic model can be applied to other complex pyrochlore materials having magnetic frustration which are leading to the formation of complex magnetic phases such as those observed at the spin glass freezing in Y [40]. The holographic model can also describe the ferrimagnetic phases in other compounds having complex magnetic structure, such as those observed in recently synthesized Pd-based ternary compounds of the form R 2 PdSi 3 , where R is a rare earth atom (see Ref.…”

Section: Apply To Real Materialsmentioning

confidence: 67%

See 1 more Smart Citation

Holographic antiferromagnetic quantum criticality andAdS2scaling limit

2015

View full text Add to dashboard Cite

A holographic description on the antiferromagnetic quantum phase transition (QPT) induced by the magnetic field and the criticality in the vicinity of the quantum critical point have been investigated numerically recently. In this paper, we show that the properties of QPT in this holographic model are governed by a CFT dual to the emergent AdS 2 in the IR region, which confirms that the dual boundary theory is a strong coupling theory with dynamic exponent z ¼ 2 and logarithmic corrections appearing. We also compare them with the results from the Hertz model by solving the RG equation at its upper critical dimension and with some experimental data from pyrochlores Er 2−2x Y 2x Ti 2 O 7 and BiCoPO 5 .

show abstract

Section: Apply To Real Materialsmentioning

confidence: 67%

“…Then using the method in Ref. [33], one can find that the retarded Green's function can be expanded in small ω as (40), the retarded Green's function can be written as the following form for small ω and q,…”

Section: B Linear Perturbations and Dynamic Exponentmentioning

confidence: 99%

Holographic antiferromagnetic quantum criticality andAdS2scaling limit

2015

View full text Add to dashboard Cite

show abstract

“…Rare earth pyrochlore oxides have been of recent interest, often with Ti or Sn on the nonmagnetic B site (i.e., materials of the type RE 2 (Ti/Sn) 2 behavior. 1,2,3,4,5 Rare earth pyrochlores are well-known for their low magnetic coupling strengths, which add a layer of complexity to the interpretation of their magnetic properties, as small changes in structure or the influence of what are nominally weak auxiliary interactions can significantly affect their ground state at low temperatures. Investigation of pyrochlore systems containing elements with larger magnetic interactions, such as transition metals, may therefore present alternative pathways in the study of magnetic frustration.…”

Section: Introductionmentioning

confidence: 99%

NaSrMn₂F₇, NaCaFe₂F₇, and NaSrFe₂F₇: novel single crystal pyrochlore antiferromagnets

Sanders

Krizan

Plumb

et al. 2016

J. Phys.: Condens. Matter

View full text Add to dashboard Cite

The crystal structures and magnetic properties of three previously unreported A 2 B 2 F 7 pyrochlore materials, NaSrMn 2 F 7 , NaCaFe 2 F 7 , and NaSrFe 2 F 7 are presented. In these compounds, either S=2 Fe 2+ or S=5/2 Mn 2+ is on the B site, while nonmagnetic Na and Ca (Na and Sr) are disordered on the A site. The materials, which were grown as crystals via the floating zone method, display high effective magnetic moments and large Curie-Weiss thetas. Despite these characteristics, freezing of the magnetic spins, characterized by peaks in the susceptibility or specific heat, is not observed until low temperatures. The empirical frustration index, f=-θcw/T f , for the materials are 36 (NaSrMn 2 F 7 ), 27 (NaSrFe 2 F 7 ), and 19 (NaCaFe 2 F 7 ). AC susceptibility, DC susceptibility, and heat capacity measurements are used to characterize the observed spin glass behavior. The results suggest that the compounds are frustrated pyrochlore antiferromagnets with weak bond disorder. The magnetic phenomena that these fluoride pyrochlores exhibit, in addition to their availability as relatively large single crystals, make them promising candidates for the study of geometric magnetic frustration.

show abstract

“…An overall experimental picture of the magnetic properties emerges. Introduction -The broad interest in geometrically frustrated magnetic materials such as pyrochlore insulator compounds R 2 M 2 O 7 (F d3m space group), where R is a rare earth ion and M a non magnetic element, arises from the large diversity of magnetic ground states and exotic fluctuations and excitations encountered [1,2,3,4,5]. This is due to the combined effects of the geometrical constraint resulting from the topology of the pyrochlore lattice and the action of the different possible interactions.…”

mentioning

confidence: 99%

A novel type of splayed ferromagnetic order observed in Yb₂Ti₂O₇

Yaouanc

Réotier

Keller

et al. 2016

J. Phys.: Condens. Matter

View full text Add to dashboard Cite

Abstract. The pyrochlore insulator Yb 2 Ti 2 O 7 has attracted the attention of experimentalists and theoreticians alike for about 15 years. Conflicting neutron diffraction data on the possible existence of magnetic Bragg reflections at low temperature have been published. Here we report the observation of magnetic Bragg reflections by neutron powder diffraction at 60 mK. The magnetic diffraction pattern is analyzed using representation theory. We find Yb 2 Ti 2 O 7 to be a splayed ferromagnet as reported for Yb 2 Sn 2 O 7 , a sibling compound with also dominating ferromagnetic interactions as inferred from the positive Curie-Weiss temperature. However, the configuration of the magnetic moment components perpendicular to the easy axis is of the all-in-all-out type in Yb 2 Ti 2 O 7 while it is two-in-two-out in Yb 2 Sn 2 O 7 . An overall experimental picture of the magnetic properties emerges. Introduction -The broad interest in geometrically frustrated magnetic materials such as pyrochlore insulator compounds R 2 M 2 O 7 (F d3m space group), where R is a rare earth ion and M a non magnetic element, arises from the large diversity of magnetic ground states and exotic fluctuations and excitations encountered [1,2,3,4,5]. This is due to the combined effects of the geometrical constraint resulting from the topology of the pyrochlore lattice and the action of the different possible interactions. As a consequence, classical and quantum fluctuations are particularly strong. Among the interactions of interest, the crystal field at the R position, the Heisenberg nearest-neighbour exchange interaction as well as its extension beyond the nearest-neighbour R ions [6,7], the anisotropy of the exchange interactions [8,9] and the inevitable dipolar interactions have been considered.The most remarkable discovery in the realm of geometrically frustrated magnetic materials has been the spin-ice ground state of Ho 2 Ti 2 O 7 in 1997 [10]. It is characterized by dipolar correlations emerging from the topological spin-ice constraint. This translates into pinch-points in the neutron diffuse scattering patterns [11] and magnetic monopole excitations [12,13,14].Because of its large ground-state degeneracy, a spin-ice compound does not order magnetically, i.e., it is in a so-called spin liquid state where the spins are strongly correlated although they do not display long range order. Quantum fluctuations are not expected to play a significant role for Ho 2 Ti 2 O 7 . However, for some pyrochlore materials strong quantum transverse fluctuations [8,9] could stabilize new magnetic states such as a quantum spin liquid for which new exotic excitations are expected [3,15,16,17,5].One of the favourite candidates for this exotic ground state is Yb 2 Ti 2 O 7 . Indeed, the exchange interactions are highly anisotropic, with a strong ferromagnetic component akin to the Ising exchange of spin ice [18].The dominating ferromagnetic component is also suggested by the positive Curie-Weiss temperature [19]. Remarkably, the Ising character of the exchan...

show abstract

Magnetic pyrochlore oxides

Cited by 1,345 publications

References 352 publications

Holographic antiferromagnetic quantum criticality andAdS2scaling limit

Holographic antiferromagnetic quantum criticality andAdS2scaling limit

NaSrMn₂F₇, NaCaFe₂F₇, and NaSrFe₂F₇: novel single crystal pyrochlore antiferromagnets

A novel type of splayed ferromagnetic order observed in Yb₂Ti₂O₇

Contact Info

Product

Resources

About

Magnetic pyrochlore oxides

Cited by 1,345 publications

References 352 publications

Holographic antiferromagnetic quantum criticality andAdS2scaling limit

Holographic antiferromagnetic quantum criticality andAdS2scaling limit

NaSrMn2F7, NaCaFe2F7, and NaSrFe2F7: novel single crystal pyrochlore antiferromagnets

A novel type of splayed ferromagnetic order observed in Yb2Ti2O7

Contact Info

Product

Resources

About

NaSrMn₂F₇, NaCaFe₂F₇, and NaSrFe₂F₇: novel single crystal pyrochlore antiferromagnets

A novel type of splayed ferromagnetic order observed in Yb₂Ti₂O₇