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Kiryukhin, V.; Kim, B. G.; Katsufuji, T.; Hill, J. P.; Cheong, Sang‐Wook

doi:10.1103/physrevb.63.144406

Cited by 23 publications

(34 citation statements)

References 19 publications

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“…The long-range AFM ordering has been confirmed by neutron scattering studies in Ref. [7]. Comparing our wðTÞ curves, we conclude that at ToT N the moments should be mainly perpendicular to the c-axis.…”

Section: Resultssupporting

confidence: 73%

Magnetism in the pseudo-two-leg ladder compound CaCu2O3

Wolf

Müller

Eckert

et al. 2005

Journal of Magnetism and Magnetic Materials

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Section: Resultssupporting

confidence: 73%

Magnetism in the pseudo-two-leg ladder compound CaCu2O3

Wolf

Müller

Eckert

et al. 2005

Journal of Magnetism and Magnetic Materials

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“…The J ring /J Ќ ratio is 0.22 for both spin-ladder compounds, and it is consistent with that proposed by Matsuda et al 15 and the bridging oxygen ones. On the other hand, the J ʈ value is Ϫ147 meV, larger than the NN coupling in 2D cuprates, and in good agreement with the estimations coming from magnetic susceptibility and neutron diffraction 22 (J ʈ ϳ Ϫ167Ϯ25 meV). Both the NNN interaction and the 4SCE are also affected by the folding.…”

supporting

confidence: 75%

Four-spin cyclic exchange in spin ladder cuprates

et al. 2003

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The four-spin cyclic exchange term J ring of three spin-ladder cuprates (SrCu 2 O 3 , Sr 2 Cu 3 O 5 , and CaCu 2 O 3 ) has been calculated from ab initio quantum chemistry calculations. For the first two compounds, a nonnegligible cyclic exchange is found, aproximately 20% of the magnetic coupling across the rungs, J Ќ , and always larger than the value obtained for two-dimensional La 2 CuO 4 system. In the case of CaCu 2 O 3 , the J ring value is quite small, due to the folding of the Cu-O-Cu rung angle, but the J ring /J Ќ ratio is also 0.2 as in the two other systems. DOI: 10.1103/PhysRevB.67.132409 PACS number͑s͒: 75.30.Et, 71.27.ϩa, 71.70.Gm, 75.50.Ee Spin-ladder cuprates constitute an active research field in the last decade.1,2 They can be viewed as intermediates between the one-dimensional ͑1D͒ antiferromagnets and the still controversial two-dimensional ͑2D͒ square lattices. Ladders composed of Cu and O are specially interesting due to their proximity to high-T c cuprates. Their magnetic properties depend on the number of legs. Even-legged ladders show a spin gap excitation, whereas odd-legged ladders are gapless and behave as a 1D spin chain.1,2 They also present different properties regarding hole doping. It has been suggested that even-legged spin ladders become superconductors upon hole doping, which has been confirmed experimentally 3 in the two-legged ladder Sr 14Ϫx Ca x Cu 24 O 41 under high pressure.The magnetic properties of these compounds are controlled by the effective magnetic coupling constant J, related with the amplitude of the interactions between the spin moments of the Cu ϩ2 ions. Different J constants can be defined, as shown in Fig. 1. The two most important are the coupling along the legs, J ʈ , and across the rungs, J Ќ . The ratio J Ќ /J ʈ is controversial since the interpretation of different experimental data has led to estimates ranging from spatially isotropic, J Ќ /J ʈ ϭ1, to strongly anisotropic couplings, J Ќ /J ʈ ϭ0.5. The strong spatial anisotropy J Ќ /J ʈ ϭ0.5 is in contradiction with geometrical considerations. Since the Cu-O-Cu bonds are quite similar, the exchange pathways are expected to be equivalent, and so, J ʈ ϳJ Ќ . The theoretical calculations of Mizuno, Tohyama, and Maekawa; 4 and de Graaf et al. 5 are in agreement with these considerations.It should be noted that most of the available J Ќ and J ʈ values have been obtained by fitting the experimental data onto a model Heisenberg Hamiltonian, containing just twobody operators. As in the case of the 2D cuprates, 6-10 some authors have recently suggested the necessity of introducing additional interactions in the model Heisenberg Hamiltonian to study the properties of the spin ladders. The most important are the diagonal coupling ͑second-neighbor interactions͒, the interladder exchange and, especially, the four-spin cyclic exchange ͑4SCE͒. In this context, de Graaf et al. 5 have proposed that the omission of the interladder coupling in the analysis of experimental data for SrCu 2 O 3 may be the reason that a...

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“…In the former, a phase separated regime interpolates between the AFM and FM phases while approaching the FM phase by hole doping of the AFM phase. When long-range Coulomb interactions are taken into account, the phase separated domains turn out to be of the order of a few nanometer size as observed in some experiments [17]. However, experimental results of Uehra et al [5] indicate the presence of much larger (Bmicrometer size) domains.…”

Section: Introductionmentioning

confidence: 90%

“…As we go into region 2, the quality of the fits to the derivative of single Lorentzian deteriorates. This may be understood in terms of the building up of FM correlations as verified by neutron diffraction [22] and by the two-dimensional nanoscopic structural correlations as proposed by Kiryukhin et al [17] based on X-ray diffraction experiments. Presence of such fluctuating FM correlations may cause distortion of a Lorentzian signal due to the fluctuating internal fields.…”

Section: Article In Pressmentioning

confidence: 98%

An electron paramagnetic resonance study of phase segregation in Nd0.5Sr0.5MnO3

Joshi

Sood

Bhat

et al. 2004

Journal of Magnetism and Magnetic Materials

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We present results of an electron paramagnetic resonance (EPR) study of Nd 1Àx Sr x MnO 3 with x ¼ 0:5 across the paramagnetic to ferromagnetic, insulator to metal transition at 260 K (T c ) and the antiferromagnetic, charge ordering transition (T N ¼ T co ) at 150 K. The results are compared with those on Nd 0.45 Sr 0.55 MnO 3 which undergoes a transition to a homogeneous A-type antiferromagnetic phase at T N ¼ 230 K and on La 0.77 Ca 0.23 MnO 3 which undergoes a transition to coexisting ferromagnetic metallic and ferromagnetic insulating phases. For x ¼ 0:5; the EPR signals below T c consist of two Lorentzian components attributable to the coexistence of two phases. From the analysis of the temperature dependence of the resonant fields and intensities, we conclude that in the mixed phase ferromagnetic and A-type antiferromagnetic (AFM) phases coexist. The x ¼ 0:55 compound shows a single Lorentzian throughout the temperature range. The signal persists for a few degrees below T N : The behaviour of the A-type AFM phase is contrasted with that of the two ferromagnetic phases present in La 0.77 Ca 0.23 MnO 3 . The comparison of behaviour of Atype AFM signal observed in both Nd 0.5 Sr 0.5 MnO 3 and Nd 0.45 Sr 0.55 MnO 3 with the two FM phases of La 0.77 Ca 0.23 MnO 3 , vis-" a-vis the shift of resonances with respect to the paramagnetic phases and the behaviour of EPR intensity as a function of temperature conclusively prove that the Nd 0.5 Sr 0.5 MnO 3 undergoes phase separation into A-type AFM and FM phases. r

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Nanoscale anisotropic structural correlations in the paramagnetic and ferromagnetic phases ofNd0.5Sr0.5
V. Kiryukhin
¹
,
B. G. Kim
²
,
T. Katsufuji³
et al.

Cited by 23 publications

References 19 publications

Magnetism in the pseudo-two-leg ladder compound CaCu2O3

Magnetism in the pseudo-two-leg ladder compound CaCu2O3

Four-spin cyclic exchange in spin ladder cuprates

An electron paramagnetic resonance study of phase segregation in Nd0.5Sr0.5MnO3

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Nanoscale anisotropic structural correlations in the paramagnetic and ferromagnetic phases ofNd0.5Sr0.5V. Kiryukhin1, B. G. Kim2, T. Katsufuji3 et al.

Cited by 23 publications

References 19 publications

Magnetism in the pseudo-two-leg ladder compound CaCu2O3

Magnetism in the pseudo-two-leg ladder compound CaCu2O3

Four-spin cyclic exchange in spin ladder cuprates

An electron paramagnetic resonance study of phase segregation in Nd0.5Sr0.5MnO3

Contact Info

Product

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Nanoscale anisotropic structural correlations in the paramagnetic and ferromagnetic phases ofNd0.5Sr0.5
V. Kiryukhin
¹
,
B. G. Kim
²
,
T. Katsufuji³
et al.