Magnetic ordering in diluted kagome antiferromagnets

Frunzke, J.; Hansen, Thomas C.; Harrison, Andrew; Lord, J. S.; Oakley, G.S.; Visser, D.; Wills, A. S.

doi:10.1039/b003195j

“…Magnetic ordering with the magnetic cell the same size as the nuclear has been observed in the compositions KFe 3 (CrO 4 ) 2 (OD) 6 11 and KCr 3 (SO 4 ) 2 (OD) 6 .…”

Section: A K = 000mentioning

confidence: 81%

“…are stabilised by ferromagnetic and antiferromagnetic exchange respectively, while the k = 000 spin structure observed in both KCr 3 (SO 4 ) 2 (OD) 6 12 and KFe 3 (CrO 4 ) 2 (OD) 6 11 is stabilised by antiferromagnetic coupling.…”

Section: +mentioning

confidence: 97%

“…Polarised neutron powder diffraction studies of (D 3 O)Fe 3 (SO 4 ) 2 (OD) 6 have shown that despite a freezing temperature of T g ∼ 17 K, short-ranged correlations are present at temperatures as high as 250 K, demonstrating well the difficulty with which the moments are freezing. 23,24 The depression of the freezing temperature with relation to the exchange energy is compatible with suggestions of the freezing being a consequence of a new energy scale-a reduced Kosterlitz-Thouless temperature-that approximates to θ/48 for an XY system.…”

Section: Unconventional Orderingsmentioning

confidence: 99%

“…While the question of the influences of disorder remains unanswered in (H 3 O)Fe 3 (SO 4 ) 2 (OH) 6 , the unconventional nature of the observed spin glass phase is manifest. It is clear that the origins of the spin glass state itself and these unconventional properties are related to the frustrated topology of the kagomé lattice.…”

Section: Unconventional Orderingsmentioning

confidence: 99%

“…k = 00 3 2 Ordering with this propagation vector is found in the majority of the iron jarosites (AFe 3 (SO 4 ) 2 (OD) 6 6 . In all the Fe compositions, ordering under the repeated first-order representation is again observed.…”

Section: 12mentioning

confidence: 99%

See 3 more Smart Citations

Conventional and unconventional orderings in the jarosites

Wills¹

2001

View full text Add to dashboard Cite

The jarosites make up the most studied family of kagomé antiferromagnets. The flexibility of the structure to substitution of the A and B ions allows a wide range of compositions to be synthesised with the general formula AB3 (SO4) (SO4) 2− groups by (SeO4) 2− or (CrO4) 2− . Thus, a variety of S = 5/2, 3/2, and 1 systems can be engineered to allow study of the effects of frustration in both the classical and more quantum limits. Within this family both conventional long-ranged magnetic order and more exotic unconventional orderings have been found. This article reviews the different types of magnetic orderings that occur and examines some of the parameters that are their cause.

show abstract

A “Star” Antiferromagnet: A Polymeric Iron(III) Acetate That Exhibits Both Spin Frustration and Long‐Range Magnetic Ordering

Zheng

¹

,

Tong

²

,

Xue

³

et al. 2007

View full text Add to dashboard Cite

The preparation of new geometrically spin-frustrated magnetic materials [1] that approximate theoretical models [1,2] is a challenge. Although the Mermin-Wagner theorem [3] indicates that long-range magnetic order can exist in two dimensions at zero Kelvin, order can be destroyed either by quantum fluctuations or geometric frustration even at this temperature. Theoretical studies indicate that the ground state of a spin-1/2 Heisenberg antiferromagnet is most likely to be semiclassically ordered.[4] However, the interplay of geometric frustration and quantum fluctuations has been found to give rise to a paramagnetic ground state without semi-classical long-range order in two types of lattice.The first of these lattices is the famous KagomØ lattice (T8) and the second is the so-called "star" lattice (T9; Scheme 1), which may serve as a new example of a quantum paramagnet. [4,5] The triangles are corner-sharing in the KagomØ lattice whereas they are separated by a bridge in the star lattice, which means that their next-nearest-neighbor exchange interactions are different. [4,5] The magnetic J exchange pathways in the KagomØ lattice are all equivalent, whereas the intra-triangular J T pathway in the star lattice is weaker than the inter-triangular J D pathway. In contrast to the rapid development of KagomØ-type antiferromagetic lattices [6, 7] and related, geometrically spin-frustrated lattices, [8] there appears to date to be no report of a compound with a genuine star lattice. [7][8][9] including the desired magnetically frustrated star lattice. This star lattice can be described in vertex notation as 3.12 2 (see Scheme S1 in the Supporting Information), a lattice that is a uniform, three-connected twodimensional net with large voids.[10] Three-connected node subunits that prefer to bond in a planar fashion, such as the basic cationic iron(III) carboxylate cluster [Fe 3 [11] where L may be water, methanol, or pyridine, must be used to avoid three-dimensional connections. These carboxylate clusters are good potential building blocks because they are easily prepared, prefer planar bonding, and the R groups and L ligands can easily be varied. [12] The cationic [Fe 3 + moiety has previously served as a six-or three-connected node (see Scheme S2 in the Supporting Information) to form either three- [12a-e] or zero-dimensional [12f] porous frameworks depending upon the nature of the carboxylate, which may be either fully or partially substituted by dicarboxylates; the L ligands are usually retained as terminal ligands. Although no example is known to date, it should be possible to substitute the L ligands located in the triangular [Fe 3

show abstract

A “Star” Antiferromagnet: A Polymeric Iron(III) Acetate That Exhibits Both Spin Frustration and Long‐Range Magnetic Ordering

Zheng

¹

,

Tong

²

,

Xue

³

et al. 2007

View full text Add to dashboard Cite

The preparation of new geometrically spin-frustrated magnetic materials [1] that approximate theoretical models [1,2] is a challenge. Although the Mermin-Wagner theorem [3] indicates that long-range magnetic order can exist in two dimensions at zero Kelvin, order can be destroyed either by quantum fluctuations or geometric frustration even at this temperature. Theoretical studies indicate that the ground state of a spin-1/2 Heisenberg antiferromagnet is most likely to be semiclassically ordered.[4] However, the interplay of geometric frustration and quantum fluctuations has been found to give rise to a paramagnetic ground state without semi-classical long-range order in two types of lattice.The first of these lattices is the famous KagomØ lattice (T8) and the second is the so-called "star" lattice (T9; Scheme 1), which may serve as a new example of a quantum paramagnet. [4,5] The triangles are corner-sharing in the KagomØ lattice whereas they are separated by a bridge in the star lattice, which means that their next-nearest-neighbor exchange interactions are different. [4,5] The magnetic J exchange pathways in the KagomØ lattice are all equivalent, whereas the intra-triangular J T pathway in the star lattice is weaker than the inter-triangular J D pathway. In contrast to the rapid development of KagomØ-type antiferromagetic lattices [6, 7] and related, geometrically spin-frustrated lattices, [8] there appears to date to be no report of a compound with a genuine star lattice. [7][8][9] including the desired magnetically frustrated star lattice. This star lattice can be described in vertex notation as 3.12 2 (see Scheme S1 in the Supporting Information), a lattice that is a uniform, three-connected twodimensional net with large voids.[10] Three-connected node subunits that prefer to bond in a planar fashion, such as the basic cationic iron(III) carboxylate cluster [Fe 3 [11] where L may be water, methanol, or pyridine, must be used to avoid three-dimensional connections. These carboxylate clusters are good potential building blocks because they are easily prepared, prefer planar bonding, and the R groups and L ligands can easily be varied. [12] The cationic [Fe 3 + moiety has previously served as a six-or three-connected node (see Scheme S2 in the Supporting Information) to form either three- [12a-e] or zero-dimensional [12f] porous frameworks depending upon the nature of the carboxylate, which may be either fully or partially substituted by dicarboxylates; the L ligands are usually retained as terminal ligands. Although no example is known to date, it should be possible to substitute the L ligands located in the triangular [Fe 3

show abstract

Magnetic ordering in diluted kagome antiferromagnets

Cited by 47 publications

References 35 publications

Conventional and unconventional orderings in the jarosites

Conventional and unconventional orderings in the jarosites

A “Star” Antiferromagnet: A Polymeric Iron(III) Acetate That Exhibits Both Spin Frustration and Long‐Range Magnetic Ordering

A “Star” Antiferromagnet: A Polymeric Iron(III) Acetate That Exhibits Both Spin Frustration and Long‐Range Magnetic Ordering

Contact Info

Product

Resources

About