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Electron pairing along with phase coherence generates superconductivity below the critical temperature ($T_c$). In underdoped high-$T_c$ cuprates, these two quantum phenomena may occur at separate temperatures, which was lately confirmed in…

We report the $^{11}$B nuclear magnetic resonance (NMR) measurements on non-centrosymmetric superconductors NbRh$_2$B$_2$ (superconducting transition temperature $T_c$ = 7.8 K) and TaRh$_2$B$_2$ ($T_c$ = 5.9 K) with a chiral crystal…

Superconductivity · Physics 2021-12-22 Kazuaki Matano , Ryo Ogura , Mateo Fountainea , Harald O. Jeschke , Shinji Kawasaki , Guo-qing Zheng

We present NMR measurements of the layered nitride superconductor Li_xZrNCl. The nuclear spin-lattice relaxation rate, 1/T_1, shows that the coherence peak is strongly suppressed in Li_xZrNCl in contrast to conventional BCS superconductors.…

We report measurements of the ^{115}In nuclear spin-lattice relaxation rate (1/T_1) between T=0.09 K and 100 K in the new heavy fermion (HF) compound CeIrIn_5. At 0.4 K < T < 100 K, 1/T_1 is strongly T-dependent, which indicates that…

Superconductivity · Physics 2009-11-07 G. -q. Zheng , K. Tanabe , T. Mito , S. Kawasaki , Y. Kitaoka , D. Aoki , Y. Haga , Y. Onuki

We report In-NQR and Co-NMR experiments of CeCoIn$_5$ that undergoes a superconducting transition with a record high $T_{\rm c}$ = 2.3 K to date among heavy-fermion superconductors. At zero magnetic field, an anomalous temperature ($T$)…

Strongly Correlated Electrons · Physics 2009-11-10 Y. Kawasaki , S. Kawasaki , M. Yashima , T. Mito , G. -q. Zheng , Y. Kitaoka , H. Shishido , R. Settai , Y. Haga , Y. Onuki

The electron-nuclear hyperfine interaction shows up in a variety of phenomena including e.g. NMR studies of correlated states and spin decoherence effects in quantum dots. Here we focus on the hyperfine coupling and the NMR spin relaxation…

Mesoscale and Nanoscale Physics · Physics 2016-12-28 Zoltán Okvátovity , Ferenc Simon , Balázs Dóra

We present a careful analysis of the temperature dependence of the nuclear spin-lattice relaxation rate $1/T_1$ in gapped quasi-1D Heisenberg antiferromagnets. It is found that in order to estimate the value of the gap correctly from…

Strongly Correlated Electrons · Physics 2007-05-23 R. Melzi , P. Carretta

We study the temperature dependence of nuclear magnetic relaxation (NMR) rates to detect a sign of topological superconductivity in doped topological insulators, such as $M$($=$Cu,Nb,Sr)$_{x}$Bi$_{2}$Se$_{3}$ and Sn$_{1-x}$In$_{x}$Te. The…

Superconductivity · Physics 2016-10-26 Yuki Nagai , Yukihiro Ota

We performed the Te-nuclear magnetic resonance, the Mo-nuclear quadrupole resonance, and the AC susceptibility in the Weyl semimetal superconductor 1T-MoTe$_2$ at pressures up to 2.17~GPa. From the temperature and pressure dependence of the…

Nuclear magnetic resonance (NMR) measurements on the $^{195}$Pt nucleus in an aligned powder of the moderately heavy-fermion material U2PtC2 are consistent with spin-triplet pairing in its superconducting state. Across the superconducting…

Superconductivity · Physics 2015-06-24 A. M. Mounce , H. Yasuoka , G. Koutroulakis , N. Ni , E. D. Bauer , F. Ronning , J. D. Thompson

We pursue the consequences of a theory in which the resonance peak observed in inelastic neutron scattering (INS) experiments on underdoped and optimally doped YBa$_2$Cu$_3$O$_{6+x}$ compounds arises from a spin-wave excitation. We find…

Strongly Correlated Electrons · Physics 2009-10-31 Dirk K. Morr , David Pines

$^{19}$F NMR measurements in SmFeAsO$_{1-x}$F$_x$, for $0.15\leq x\leq 0.2$, are presented. The nuclear spin-lattice relaxation rate $1/T_1$ increases upon cooling with a trend analogous to the one already observed in…

Superconductivity · Physics 2010-03-22 G. Prando , P. Carretta , A. Rigamonti , S. Sanna , A. Palenzona , M. Putti , M. Tropeano

A systematic muon-spin-relaxation study in Bi-2201 high-Tc cuprates has revealed for the first time that the Cu-spin correlation (CSC) is developed at low temperatures below 2 K in a wide range of hole concentration where superconductivity…

Superconductivity · Physics 2015-05-20 T. Adachi , Y. Tanabe , K. Suzuki , Y. Koike , T. Suzuki , T. Kawamata , I. Watanabe

We studied the nuclear relaxation rate 1/T1 of a ferromagnetic-superconducting system from the mean field model proposed in Ref.14. This model predicts the existence of a set of gapless excitations in the energy spectrum which will affect…

Superconductivity · Physics 2009-11-10 Hari P. Dahal , Jason Jackiewicz , Kevin S. Bedell

Motivated by recent attention to a potential antiferromagnetic quantum critical point at $x_c\sim 0.19$, we have used inelastic neutron scattering to investigate the low-energy spin excitations in crystals of La$_{2-x}$Sr$_x$CuO$_4$…

Superconductivity · Physics 2018-12-17 Yangmu Li , Ruidan Zhong , M. B. Stone , A. I. Kolesnikov , G. D. Gu , I. A. Zaliznyak , J. M. Tranquada

We report 75As-nuclear quadrupole resonance (NQR) studies on (Ca_4Al_2O_{6-y})(Fe_2As_2) with Tc=27K, which unravel unique normal-state properties and point to unconventional nodeless superconductivity (SC). Measurement of…

Superconductivity · Physics 2015-05-28 H. Kinouchi , H. Mukuda , M. Yashima , Y. Kitaoka , P. M. Shirage , H. Eisaki , A. Iyo

Non-centrosymmetric superconductor Re$_6$Zr has attracted much interest, for its possible unconventional superconducting state with time reversal symmetry broken. Here we report the $^{185/187}$Re nuclear quadrupole resonance (NQR)…

Superconductivity · Physics 2016-12-26 K. Matano , R. Yatagai , S. Maeda , Guo-qing Zheng

Superconductivity appears to compete against the spin-density-wave in Fe pnictides. However, optimally cobalt doped samples show a quasi-two-dimensional spin excitation centered at the (0.5, 0.5, L) wavevector, "the spin resonance peak",…

We present a unified description of the resonance peak and low-energy incommensurate response observed in high-$T_c$ cuprate superconductors. We argue that both features have a purely magnetic origin and they represent universal features of…

Superconductivity · Physics 2009-10-31 C. D. Batista , G. Ortiz , A. V. Balatsky

Spin fluctuation-induced superconductivity in quasi-two dimensional organic compounds, \kappa-BEDT-TTF salts, is investigated within a fluctuation exchange (FLEX) approximation using a half-filled Hubbard model with a right-angled isosceles…

Superconductivity · Physics 2016-08-15 Hisashi Kondo , Tôru Moriya