skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Potential Antiferromagnetic Fluctuations in Hole-Doped Iron-Pnictide Superconductor Ba1-xKxFe2As2 Studied by 75As Nuclear Magnetic Resonance Measurement0.1143/JPSJ.81.054704

Abstract

We have performed 75As nuclear magnetic resonance (NMR) and nuclear quadrupole resonance (NQR) measurements on single-crystalline Ba1-xKxFe2As2 for x = 0.27–1. 75As nuclear quadruple resonance frequency (νQ) increases linearly with increasing x. The Knight shift K in the normal state shows Pauli paramagnetic behavior with a weak temperature T dependence. K increases gradually with increasing x. By contrast, the nuclear spin–lattice relaxation rate 1/T1 in the normal state has a strong T dependence, which indicates the existence of large antiferomagnetic (AF) spin fluctuations for all x's. The T dependence of 1/T1 shows a gaplike behavior below approximately 100 K for 0.6 < x < 0.9. This behaviors is well explained by the change in the band structure with the expansion of hole Fermi surfaces and the shrinkage and disappearance of electron Fermi surfaces at the Brillouin zone (BZ) with increasing x. The anisotropy of 1/T1, represented by the ratio of 1/T1ab to 1/T1c, is always larger than 1 for all x's, which indicates that stripe-type AF fluctuations are dominant in this system. The K in the superconducting (SC) state decreases, which corresponds to the appearance of spin-singlet superconductivity. The T dependence of 1/T1 in the SC state indicates a multiple-SC-gapmore » feature. A simple two-gap model analysis shows that the larger superconducting gap gradually decreases with increasing x from 0.27 to 1 and a smaller gap decreases rapidly and nearly vanishes for x > 0.6 where electron pockets in BZ disappear.« less

Authors:
; ; ; ; ; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
Ames Laboratory (AMES), Ames, IA (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1045006
Report Number(s):
IS-J 7684
DOE Contract Number:  
DE-AC02-07CH11358
Resource Type:
Journal Article
Journal Name:
Journal of Physical Society of Japan
Additional Journal Information:
Journal Volume: 81
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE

Citation Formats

Hirano, Masanori, Yamada, Yuji, Saito, Taku, Nagashima, Ryo, Konishi, Takehisa, Toriyama, Tatsuya, Ohta, Yukinori, Fukazawa, Hideto, Kohori, Yoh, Furukawa, Yuji, Kihou, Kunihiro, Lee, Chul-Ho, and Eisaki, Hiroshi. Potential Antiferromagnetic Fluctuations in Hole-Doped Iron-Pnictide Superconductor Ba1-xKxFe2As2 Studied by 75As Nuclear Magnetic Resonance Measurement0.1143/JPSJ.81.054704. United States: N. p., 2012. Web. doi:10.1143/JPSJ.81.054704.
Hirano, Masanori, Yamada, Yuji, Saito, Taku, Nagashima, Ryo, Konishi, Takehisa, Toriyama, Tatsuya, Ohta, Yukinori, Fukazawa, Hideto, Kohori, Yoh, Furukawa, Yuji, Kihou, Kunihiro, Lee, Chul-Ho, & Eisaki, Hiroshi. Potential Antiferromagnetic Fluctuations in Hole-Doped Iron-Pnictide Superconductor Ba1-xKxFe2As2 Studied by 75As Nuclear Magnetic Resonance Measurement0.1143/JPSJ.81.054704. United States. doi:10.1143/JPSJ.81.054704.
Hirano, Masanori, Yamada, Yuji, Saito, Taku, Nagashima, Ryo, Konishi, Takehisa, Toriyama, Tatsuya, Ohta, Yukinori, Fukazawa, Hideto, Kohori, Yoh, Furukawa, Yuji, Kihou, Kunihiro, Lee, Chul-Ho, and Eisaki, Hiroshi. Thu . "Potential Antiferromagnetic Fluctuations in Hole-Doped Iron-Pnictide Superconductor Ba1-xKxFe2As2 Studied by 75As Nuclear Magnetic Resonance Measurement0.1143/JPSJ.81.054704". United States. doi:10.1143/JPSJ.81.054704.
@article{osti_1045006,
title = {Potential Antiferromagnetic Fluctuations in Hole-Doped Iron-Pnictide Superconductor Ba1-xKxFe2As2 Studied by 75As Nuclear Magnetic Resonance Measurement0.1143/JPSJ.81.054704},
author = {Hirano, Masanori and Yamada, Yuji and Saito, Taku and Nagashima, Ryo and Konishi, Takehisa and Toriyama, Tatsuya and Ohta, Yukinori and Fukazawa, Hideto and Kohori, Yoh and Furukawa, Yuji and Kihou, Kunihiro and Lee, Chul-Ho and Eisaki, Hiroshi},
abstractNote = {We have performed 75As nuclear magnetic resonance (NMR) and nuclear quadrupole resonance (NQR) measurements on single-crystalline Ba1-xKxFe2As2 for x = 0.27–1. 75As nuclear quadruple resonance frequency (νQ) increases linearly with increasing x. The Knight shift K in the normal state shows Pauli paramagnetic behavior with a weak temperature T dependence. K increases gradually with increasing x. By contrast, the nuclear spin–lattice relaxation rate 1/T1 in the normal state has a strong T dependence, which indicates the existence of large antiferomagnetic (AF) spin fluctuations for all x's. The T dependence of 1/T1 shows a gaplike behavior below approximately 100 K for 0.6 < x < 0.9. This behaviors is well explained by the change in the band structure with the expansion of hole Fermi surfaces and the shrinkage and disappearance of electron Fermi surfaces at the Brillouin zone (BZ) with increasing x. The anisotropy of 1/T1, represented by the ratio of 1/T1ab to 1/T1c, is always larger than 1 for all x's, which indicates that stripe-type AF fluctuations are dominant in this system. The K in the superconducting (SC) state decreases, which corresponds to the appearance of spin-singlet superconductivity. The T dependence of 1/T1 in the SC state indicates a multiple-SC-gap feature. A simple two-gap model analysis shows that the larger superconducting gap gradually decreases with increasing x from 0.27 to 1 and a smaller gap decreases rapidly and nearly vanishes for x > 0.6 where electron pockets in BZ disappear.},
doi = {10.1143/JPSJ.81.054704},
journal = {Journal of Physical Society of Japan},
number = ,
volume = 81,
place = {United States},
year = {2012},
month = {4}
}