Study of charge and spin order in La2NiO4+δ using 139La-NMR

Bernal, O. O.; Brom, H.B.; Kök, Mediha; Witteveen, J.; Menovsky, A.A.

doi:10.1016/s0921-4534(97)00790-9

Cited by 8 publications

(6 citation statements)

References 9 publications

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“…6. The susceptibility on samples with well-known oxygen stoichiometries has been published by Odier et al, 37 and for samples similar to ours by Bernal et al and Abu-Shiekah et al 7,38 For La 2 NiO 4.17 the χ data are in good agreement with each other, and can be described by a Curie-Weiss law with an almost T -independent background χ 0 . The central positions at 54.75 MHz for B c and 55.55 / 55.90 MHz for B ⊥ c at 250 K are hardly T or χ dependent.…”

Section: B Doped La2nio4supporting

confidence: 81%

The susceptibility - Knight-shift relation in La2NiO4.17 and K2NiF4 by 61Ni NMR

van der Klink,

Brom

2010

Preprint

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The NiO4 plaquettes in La2NiO4.17, a cousin of the hole-doped high-temperature superconductor La2−xSrxCuO4, have been studied by 61 Ni-NMR in 14 T in a single crystal enriched in 61 Ni. Doped and undoped plaquettes are discriminated by the shift of the NMR resonance, leading to a small line splitting, which hardly depends on temperature or susceptibility. The smallness of the effect is additional evidence for the location of the holes as deduced by Schüssler-Langenheine et al., Phys. Rev. Lett. 95, 156402 (2005). The increase in linewidth with decreasing temperature shows a local field redistribution, consistent with the formation of charge density waves or stripes. For comparison, we studied in particular the grandmother of all planar antiferromagnets K2NiF4 in the paramagnetic state using natural abundant 61 Ni. The hyperfine fields in both 2-dimensional compounds appear to be remarkably small, which is well explained by super(transferred) hyperfine interaction. In K2NiF4 the temperature dependence of the susceptibility and Knight shift cannot be brought onto a simple scaling curve. This unique feature is ascribed to a different sensitivity for correlations of these two parameters.

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Section: B Doped La2nio4supporting

confidence: 81%

The susceptibility - Knight-shift relation in La2NiO4.17 and K2NiF4 by 61Ni NMR

van der Klink,

Brom

2010

Preprint

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“…The so obtained internal field of 1.6 T agrees well with the internal field of about 1.78 T reported by Wada et al [19] for La 2 NiO 4.10 . Also by comparing our susceptibility and linewidth data at high temperature we can estimate the hyperfine field to be about 2.0 T, consistent with the earlier quoted values [13]. Using a hyperfine field of 1.8 T, the fit to the relaxation data gives a value of 2600 s −1 for γ 2 n h 2 0 τ ∞ , and hence τ ∞ = 1.8 × 10 −11 s. T −1 2 has almost the same T dependence as T −1 1 .…”

supporting

confidence: 91%

“…The spectra can be decomposed into 2 La sites, one with resolved satellites and the other with overlap-ping lines due to much stronger magnetic broadening. Magnetic freezing or ordering is also visible in the bulk magnetic susceptibility, which starts to deviate from the Curie law and peaks at T = 17 ± 3 K [9,13,25]. The peak in −dχ/dT indicates a series of cusps at different spin freezing temperatures close to 17 K and can be due to spin frustration or spin clusters [25].…”

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confidence: 99%

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First Time Determination of the Microscopic Structure of a Stripe Phase: Low Temperature NMR inLa2NiO4.17

Abu-Shiekah¹,

Bakharev²,

Brom³

et al. 2001

Phys. Rev. Lett.

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The experimental observations of stripes in superconducting cuprates and insulating nickelates clearly show the modulation in charge and spin density. However, these have proven to be rather insensitive to the harmonic structure and (site or bond) ordering. Using (139)La NMR in La(2)NiO(4+delta) with delta = 0.17, we show that in the 1/3 hole doped nickelate below the freezing temperature the stripes are strongly solitonic and site ordered with Ni(3+) ions carrying S = 1/2 in the domain walls and Ni(2+) ions with S = 1 in the domains.

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“…139 La has a nuclear spin I = 7/2, which makes NMR sensitive to both charge and spin, and allows the study of charge and spin order and also the dynamics at time scales longer than 10 −7 s −1 . The measurements were performed on two single crystals from different batches that were prepared under atmospheric condition in a mirror oven at 1100 K [12]. Slices from both samples were analyzed by microprobe techniques; on the average the oxygen contents were found to be the same.…”

mentioning

confidence: 99%

Similarity of Slow Stripe Fluctuations between Sr-Doped Cuprates and Oxygen-Doped Nickelates

et al. 1999

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Stripe fluctuations in La 2 NiO 4.17 have been studied by 139 La NMR using the field and temperature dependence of the linewidth and relaxation rates. In the formation process of the stripes, the NMR line intensity is maximal below 230 K, starts to diminish around 140 K, disappears around 50 K, and recovers at 4 K. These results are shown to be consistent with, but completely complementary to, neutron measurements, and to be generic for oxygen-doped nickelates and underdoped cuprates. 74.72.Dn, 75.30.Ds, 75.40.Gb Evidence is accumulating that the electron systems in doped Mott-Hubbard insulators exhibit quite complex ordering phenomena [1]. In two-dimensional (2D) systems this takes the form of stripe phases, where the excess charges bind to antiphase boundaries in the Néel state [2]. It was recently demonstrated by Hunt et al. [3] that in a large temperature regime where the stripe order appears to be complete according to diffraction experiments, the stripe system is still slowly fluctuating. This follows from nuclear magnetic resonance (NMR) experiments, showing both motional narrowing at higher temperatures and a wipeout of the NMR signal upon cooling down, caused by the characteristic fluctuation frequency becoming of the order of the nuclear quadrapole resonance (NQR) linewidth/splitting of a few MHz. Here we will demonstrate that these fluctuations are not unique to cuprate stripes and thereby are unrelated to intricacies associated with the proximity of the superconducting state. We present a NMR study of the stripe phase in oxygen doped La 2 NiO 4 . It seems well established that the excess oxygen enters as an interstitial that shows a tendency to order three dimensionally, creating a larger unit cell [4][5][6][7]. It should therefore be regarded as a rather clean system compared to the Sr-doped nickelates [8]. We find that this "clean" nickelate system exhibits a fluctuation behavior which closely parallels the fluctuations of the cuprate stripes: although neutron-scattering experiments in La 2 NiO 4.13 [7] show charge and spin freezing at T CO 220 K and T SO 110 K, our NMR experiments in La 2 NiO 4.17 indicate that the stripes become static only at a temperature of 2 K. Interestingly, these slow fluctuations seem absent in the "dirty" Sr-doped nickelate La 5͞3 Sr 1͞3 NiO 4 [9] (with the same 1͞3 hole doping content as our oxygen-doped nickelate), where muon spin resonance ͑mSR͒ [10] measurements reveal the onset of static spin order at the same temperature (200 K) as the (quasi)elastic peaks develop in the neutron scattering [11]. These observations suggest that the slow stripe fluctuations, characteristic for the cuprates and oxygen-doped nickelates, are in the first instance unrelated to quenched disorder; at the same time, that disorder is excessively effective in pinning these slow, intrinsic fluctuations in the insulator but not in the (super)conductor.Below we analyze the field and temperature dependence of the 139 La linewidth and relaxation rates for La 2 NiO 41d with d 0.17. 139 La has...

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Study of charge and spin order in La2NiO4+δ using 139La-NMR

Cited by 8 publications

References 9 publications

The susceptibility - Knight-shift relation in La2NiO4.17 and K2NiF4 by 61Ni NMR

The susceptibility - Knight-shift relation in La2NiO4.17 and K2NiF4 by 61Ni NMR

First Time Determination of the Microscopic Structure of a Stripe Phase: Low Temperature NMR inLa2NiO4.17

Similarity of Slow Stripe Fluctuations between Sr-Doped Cuprates and Oxygen-Doped Nickelates

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