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Granroth, G. E.; Maegawa, Satoru; Meisel, Mark W.; Krzystek, J.; Brunel, Louis‐Claude; Bell, Nelson S.; Adair, James H.; Ward, Brian H.; Fanucci, Gail E.; Chou, L.-K.; Talham, Daniel R.

doi:10.1103/physrevb.58.9312

Cited by 17 publications

(14 citation statements)

References 28 publications

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“…In the cases where very high sensitivity is not requested the single-pass approach is applicable and a number of successful examples are found in literature in which this technique gives valuable insights into a variety of physical systems [13,[16][17][18][19][20][21][22][23][24][25][26]. With this technique it is possible to detect the number of spins which is generally higher than 10 12 spin/mT and seldom one order of magnitude lower.…”

Section: Introductionmentioning

confidence: 98%

Whispering gallery mode dielectric resonators in EMR spectroscopy above 150 GHz: Problems and perspectives

Annino¹,

Cassettari²,

Fittipaldi³

et al. 2000

Appl. Magn. Reson.

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At frequencies above 150 GHz conventional microwave techniques become unsuitable for electron magnetic resonance (EMR) spectroscopy applications. Quasi-optical techniques are the general frame into which the different approaches to high-field high-frequency EMR (HF Z -EMR) have been developed. Beyond the single-pass approach the existing HFZ-EMR spectrometers make use of Fabry-Perot resonators. In this paper the use of an alternative resonating structure on the basis of the use of whispering gallery mode dielectric resonators is shown. The physics of these resonators and their implementation in a HF2-EMR probe head are described. Their use in HFZ-EMR experiments performed on standard samples is described and the results of these experiments critically discussed in order to have insight into the open problems of the employed spectrometer; the more promising solutions to these problems, actually under development, are briefly outlined.

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Section: Introductionmentioning

confidence: 98%

Whispering gallery mode dielectric resonators in EMR spectroscopy above 150 GHz: Problems and perspectives

Annino¹,

Cassettari²,

Fittipaldi³

et al. 2000

Appl. Magn. Reson.

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“…Doping of PbNi2V20 s could be realized by a partial replacement of Ni 2 § (S = 1) with Mg 2+ (S = 0) resulting in a PbNi2_xMgxV20 s. On the basis of the valence-bond picture [6] it is known for a long time that the introduction of nonmagnetic impurities into the Haldane chain releases two S = 1/2 spins on each side of the impurity [7,8]. These spins have been indeed detected in PbNi2_xMgxV20 s by earlier electron spin resonance (ESR) measurements [9,10].…”

Section: Introductionmentioning

confidence: 99%

X-Band ESR and51V NMR study of the Haldane system PbNi2−xMgxV2O8

2004

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The temperature and angular dependence of the X-band electron spin resonance (ESR) and 5~V nuclear magnetic resonance (NMR) spectra have been measured in a recently discovered Haldanegap system, PbNi2_xMgxV208 (0 < x < 0.24). The angular dependence of the ESR signal suggests that both the spin diffusion as well as the magnetic anisotropy determine the electronic spin correlation functions. However, in doped samples the magnetic anisotropy increasingly dominates the spin dynamics on cooling. The huge broadening of the 5~V NMR spectra in doped samples at low temperatures provides evidence for localized magnetic moments in the vicinity of the Mg impurities. Locally distorted structure around each Mg impurity may slightly modify the magnetic interactions and be potentially responsible for the antiferromagnetic ordering (below T N ~ 3.5 K) in doped compositions.

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“…Again by means of numerical calculations, such as Monte Carlo [4] and density matrix renormalization group [5][6][7], it has been shown that in chains with a finite number of spins a staggered magnetization, exponentially decaying from the boundaries, should be induced by a homogeneous magnetic field. Evidence of these boundary effects have been achieved by electron spin resonance (ESR) spectra [8][9][10]. The resolution in these experiments, however, was not large enough to allow an identification of the local magnetization (Sf) pertaining to different chain sites i.…”

Section: Introductionmentioning

confidence: 99%

Boundary effects in finite Heisenberg antiferromagneticS = 1 chains:89Y NMR in Y2BaNi1−xMgxO5

et al. 2000

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By means of 89 Y nuclear magnetic resonance (NMR) spectra direct evidence of staggered magnetization induced by a uniform field has been obtained in the Heisenberg antiferromagnetic S = 1 chain YZBaNi, Mg,05 . A correspondence between the resonance lines and the lattice positions is established, providing an image of the alternating magnetic moments that develop around the Mg impurities at the chain boundaries. The amplitude of these moments is found to decrease exponentially from the edges, with a characteristic decay distance equal to the magnetic correlation length numerically evaluated for an infinite chain. While the magnetization pertaining to ions far from the boundaries behaves as in typical gapped systems, the edge spins exhibit an S = 1/2 Curie-like deviation. These results promote the NMR approach to access the spin-spin correlation function in antiferromagnetic quantum spin systems at finite temperatures.

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Magnetic studies of end-chain spin effects in the Haldane-gap materialNi(C3H10

Cited by 17 publications

References 28 publications

Whispering gallery mode dielectric resonators in EMR spectroscopy above 150 GHz: Problems and perspectives

Whispering gallery mode dielectric resonators in EMR spectroscopy above 150 GHz: Problems and perspectives

X-Band ESR and51V NMR study of the Haldane system PbNi2−xMgxV2O8

Boundary effects in finite Heisenberg antiferromagneticS = 1 chains:89Y NMR in Y2BaNi1−xMgxO5

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