Dataset Information

High-energy spin fluctuation in low-T_c iron-based superconductor LaFePO_0.9.

ABSTRACT: Spin fluctuations are widely believed to play an important role in the superconducting mechanisms of unconventional high temperature superconductors. Spin fluctuations have been observed in iron-based superconductors as well. However, in some iron-based superconductors such as LaFePO_0.9, they have not been observed by inelastic neutron scattering (INS). LaFePO_0.9 is an iron-based superconductor with a low superconducting transition temperature (T_c?=?5?K), where line nodes are observed in the superconducting gap function. The line-node symmetry typically originates from sign reversal of the order parameter in spin-fluctuation-mediated superconductivity. This contradiction has been a long-standing mystery of this superconductor. Herein, spin fluctuations were found at high energies such as 30-50?meV with comparable intensities to an optimally doped LaFeAs(O, F). Based on this finding, the line-node symmetry can be explained naturally as spin-fluctuation-mediated superconductivity.

SUBMITTER: Ishikado M

PROVIDER: S-EPMC6218523 | biostudies-literature | 2018 Nov

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

High-energy spin fluctuation in low-Tc iron-based superconductor LaFePO0.9.

Ishikado Motoyuki M Shamoto Shin-Ichi SI Kodama Katsuaki K Kajimoto Ryoichi R Nakamura Mitsutaka M Hong Tao T Mutka Hannu H

Scientific reports 20181105 1

Spin fluctuations are widely believed to play an important role in the superconducting mechanisms of unconventional high temperature superconductors. Spin fluctuations have been observed in iron-based superconductors as well. However, in some iron-based superconductors such as LaFePO0.9, they have not been observed by inelastic neutron scattering (INS). LaFePO0.9 is an iron-based superconductor with a low superconducting transition temperature (Tc = 5 K), where l ...[more]

PMID: 30397220

Similar Datasets

Project description:BackgroundLiver iron concentration (LIC) measured by MRI has become the clinical reference standard for managing iron overload in chronically transfused patients. Transverse relaxivity (R2 or R2* ) measurements are converted to LIC units using empirically derived calibration curves.HypothesisThat flip angle (FA) error due to B1+ spatial heterogeneity causes significant LIC quantitation error. B1+ scale (b1 , [FAactual /FAspecified ]) variation is a major problem at 3 T which could reduce the accuracy of transverse relaxivity measurements.Study typeProspective.PopulationForty-seven subjects with chronic transfusional iron overload undergoing clinically indicated LIC assessment.Field strength/sequence5 T/3 T dual-repetition time B1+ mapping sequence ASSESSMENT: We quantified the average/standard deviation b1 in the right and left lobes of the liver from B1+ maps acquired at 1.5 T and 3 T. The impact of b1 variation on spin echo LIC estimates was determined using a Monte Carlo model.Statistical testsMean, median, and standard deviation in whole liver and right and left lobes; two-sided t-test between whole-liver b1 means.ResultsAverage b1 within the liver was 99.3% ± 12.3% at 1.5 T versus 69.6% ± 14.6% at 3 T and was independent of iron burden (P < 0.05). Monte Carlo simulations demonstrated that b1 systematically increased R2 estimates at lower LIC (<~25 mg/g at 1.5 T, <~15 mg/g at 3 T) but flattened or even inverted the R2 -LIC relationship at higher LIC (≥~25 mg/g to 1.5 T, ≥~15 mg/g to 3 T); changes in the R2 -LIC relationship were symmetric with respect to over and under excitation and were similar at 1.5 T and 3 T (for the same R2 value). The R2* -LIC relationship was independent of b1 .ConclusionSpin echo R2 measurement of LIC at 3 T is error-prone without correction for b1 errors. The impact of b1 error on current 1.5 T spin echo-based techniques for LIC quantification is large enough to introduce measurable intersubject variability but the in vivo effect size needs a dedicated validation study.Level of evidence: 1Technical efficacy stage2.

Dataset Information

High-energy spin fluctuation in low-T_c iron-based superconductor LaFePO_0.9.

Publications

High-energy spin fluctuation in low-T<sub>c</sub> iron-based superconductor LaFePO<sub>0.9</sub>.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets