Publications
Our work on Disorder in quantum critical superconductors was featured on the cover page of Nature Physics.
121.
Curro, NJ; Hammel, PC; Pagliuso, PG; Sarrao, JL; Thompson, JD; Fisk, Z
Evidence for spiral magnetic order in the heavy fermion material CeRhIn$_5$ Journal Article
In: Phys. Rev. B, vol. 62, no. 10, pp. R6100–R6103, 2000, ISSN: 0163-1829.
@article{Curro2000a,
title = {Evidence for spiral magnetic order in the heavy fermion material CeRhIn$_5$},
author = {NJ Curro and PC Hammel and PG Pagliuso and JL Sarrao and JD Thompson and Z Fisk},
doi = {10.1103/PhysRevB.62.R6100},
issn = {0163-1829},
year = {2000},
date = {2000-09-01},
journal = {Phys. Rev. B},
volume = {62},
number = {10},
pages = {R6100--R6103},
abstract = {We report In-115 nuclear quadrupolar resonance measurements of the heavy fermion compound CeRhIn$_5$ in the paramagnetic and antiferromagnetic states. The magnetic order is consistent with a model of helical modulation of the Ce moments that is incommensurate with the lattice, and the magnetic dynamics indicate possible two-dimensional behavior.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
We report In-115 nuclear quadrupolar resonance measurements of the heavy fermion compound CeRhIn$_5$ in the paramagnetic and antiferromagnetic states. The magnetic order is consistent with a model of helical modulation of the Ce moments that is incommensurate with the lattice, and the magnetic dynamics indicate possible two-dimensional behavior.
122.
Curro, NJ; Milling, C; Haase, J; Slichter, CP
Local-field dependence of the O-17 spin-lattice relaxation and echo decay rates in the mixed state of YBa$_2$Cu$_3$O$_7$ Journal Article
In: Phys. Rev. B, vol. 62, no. 5, pp. 3473–3479, 2000, ISSN: 0163-1829.
@article{Curro2000c,
title = {Local-field dependence of the O-17 spin-lattice relaxation and echo decay rates in the mixed state of YBa$_2$Cu$_3$O$_7$},
author = {NJ Curro and C Milling and J Haase and CP Slichter},
doi = {10.1103/PhysRevB.62.3473},
issn = {0163-1829},
year = {2000},
date = {2000-08-01},
journal = {Phys. Rev. B},
volume = {62},
number = {5},
pages = {3473--3479},
abstract = {We find that the planar and apical O-17 NMR spin-lattice relaxation rate (1/T-1) and the spin-echo decay rate (1/T-2) are spatially dependent in the mixed state of YBa2Cu3O7 For both sites, 1/T-1 and 1/T-2 increase by a factor of 2 to 3 for nuclei close to the vortex cores. The data suggest that fluctuating fields from the low-frequency vibrations of the vortex lattice give rise to the similar echo decay observed at both sites. These vibrations also dominate 1/T-1 for both sites below T less than or similar to 25K. Above this temperature, the planar 1/T-1 is dominated by spin-flip scattering with delocalized quasiparticles associated with the nodes in the superconducting gap showing that the position dependence arises from the effect of the supercurrents on the quasiparticle energy spectrum.},
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tppubtype = {article}
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We find that the planar and apical O-17 NMR spin-lattice relaxation rate (1/T-1) and the spin-echo decay rate (1/T-2) are spatially dependent in the mixed state of YBa2Cu3O7 For both sites, 1/T-1 and 1/T-2 increase by a factor of 2 to 3 for nuclei close to the vortex cores. The data suggest that fluctuating fields from the low-frequency vibrations of the vortex lattice give rise to the similar echo decay observed at both sites. These vibrations also dominate 1/T-1 for both sites below T less than or similar to 25K. Above this temperature, the planar 1/T-1 is dominated by spin-flip scattering with delocalized quasiparticles associated with the nodes in the superconducting gap showing that the position dependence arises from the effect of the supercurrents on the quasiparticle energy spectrum.
123.
Curro, NJ; Hammel, PC; Suh, BJ; Hucker, M; Buchner, B; Ammerahl, U; Revcolevschi, A
Inhomogeneous low frequency spin dynamics in La$_1.65$Eu$_0.2$Sr$_0.15$CuO$_4$ Journal Article
In: Phys. Rev. Lett., vol. 85, no. 3, pp. 642–645, 2000, ISSN: 0031-9007.
@article{Curro2000b,
title = {Inhomogeneous low frequency spin dynamics in La$_1.65$Eu$_0.2$Sr$_0.15$CuO$_4$},
author = {NJ Curro and PC Hammel and BJ Suh and M Hucker and B Buchner and U Ammerahl and A Revcolevschi},
doi = {10.1103/PhysRevLett.85.642},
issn = {0031-9007},
year = {2000},
date = {2000-07-01},
journal = {Phys. Rev. Lett.},
volume = {85},
number = {3},
pages = {642--645},
abstract = {We report Cu and La nuclear magnetic resonance measurements in the title compound that reveal an inhomogeneous glassy behavior of the spin dynamics. A low temperature peak in the La spin lattice relaxation rate and the ``wipeout'' of Cu intensity both arise from these slow electronic spin fluctuations that reveal a distribution of activation energies. Inhomogeneous slowing of spin fluctuations appears to be a general feature of doped lanthanum cuprate.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
We report Cu and La nuclear magnetic resonance measurements in the title compound that reveal an inhomogeneous glassy behavior of the spin dynamics. A low temperature peak in the La spin lattice relaxation rate and the ``wipeout'' of Cu intensity both arise from these slow electronic spin fluctuations that reveal a distribution of activation energies. Inhomogeneous slowing of spin fluctuations appears to be a general feature of doped lanthanum cuprate.
124.
Curro, N. J.; Hammel, P. C.
Cu NMR echo decay in stripe ordered La$_1.65$Eu$_ 0.2$Sr$_0.15$CuO$_ 4$ Journal Article
In: Phys. C: Supercond. Its Appl., vol. 341-348 (III), pp. 1797–1798, 2000, ISSN: 0921-4534.
@article{Curro2000d,
title = {Cu NMR echo decay in stripe ordered La$_1.65$Eu$_ 0.2$Sr$_0.15$CuO$_ 4$},
author = {N. J. Curro and P. C. Hammel},
doi = {10.1016/S0921-4534(00)01084-4},
issn = {0921-4534},
year = {2000},
date = {2000-00-01},
booktitle = {International Conference on Materials and Mechanisms of Superconductivity High Temperature Superconductors VI; Feb 20-Feb 25 2000; Houston, TX, USA},
journal = {Phys. C: Supercond. Its Appl.},
volume = {341-348 (III)},
pages = {1797--1798},
publisher = {Amsterdam, Netherlands : Elsevier Science Publishers B.V., 2000},
abstract = {The Cu NMR echo decay in rare earth co-doped lanthanum cuprate undergoes a crossover from Gaussian to exponential decay below T ~ 100K. This behavior indicates that the visible nuclei are coupled to others with much faster spin lattice relaxation rates. We interpret the NMR signal as arising solely from regions on the boundaries of large clusters of coupled electron spins.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The Cu NMR echo decay in rare earth co-doped lanthanum cuprate undergoes a crossover from Gaussian to exponential decay below T ~ 100K. This behavior indicates that the visible nuclei are coupled to others with much faster spin lattice relaxation rates. We interpret the NMR signal as arising solely from regions on the boundaries of large clusters of coupled electron spins.
125.
Haase, J; Curro, NJ; Slichter, CP
Double resonance probes for close frequencies Journal Article
In: J. Magn. Reson., vol. 135, no. 2, pp. 273–279, 1998, ISSN: 1090-7807.
@article{Haase1998,
title = {Double resonance probes for close frequencies},
author = {J Haase and NJ Curro and CP Slichter},
doi = {10.1006/jmre.1998.1579},
issn = {1090-7807},
year = {1998},
date = {1998-12-01},
journal = {J. Magn. Reson.},
volume = {135},
number = {2},
pages = {273--279},
abstract = {A new double resonance probe design for NMR experiments for systems with close resonance frequencies is introduced. The design is based on two coupled resonators and was extensively tested on magnetically aligned powders of several high temperature superconductors by performing double resonance experiments between the (CU)-C-65 and (CU)-C-63 isotopes as well as between transitions of different magnetic quantum number of the same spin. The probe's performance approaches that of a single resonance circuit and it has only 4 variable tuning/matching elements. (C) 1998 Academic Press.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
A new double resonance probe design for NMR experiments for systems with close resonance frequencies is introduced. The design is based on two coupled resonators and was extensively tested on magnetically aligned powders of several high temperature superconductors by performing double resonance experiments between the (CU)-C-65 and (CU)-C-63 isotopes as well as between transitions of different magnetic quantum number of the same spin. The probe's performance approaches that of a single resonance circuit and it has only 4 variable tuning/matching elements. (C) 1998 Academic Press.
126.
Haase, J; Curro, NJ; Stern, R; Slichter, CP
New double resonance technique for quadrupolar nuclei Journal Article
In: Mol. Phys., vol. 95, no. 5, pp. 891–896, 1998, ISSN: 0026-8976.
@article{Haase1998b,
title = {New double resonance technique for quadrupolar nuclei},
author = {J Haase and NJ Curro and R Stern and CP Slichter},
doi = {10.1080/002689798166512},
issn = {0026-8976},
year = {1998},
date = {1998-12-01},
journal = {Mol. Phys.},
volume = {95},
number = {5},
pages = {891--896},
abstract = {New double resonance techniques for the resolution enhancement of nuclear magnetic resonance of quadrupolar nuclei are presented which use population transfers between Zeeman levels of a quadrupolar split spin system. Experiments on high temperature superconductors are reported where a differentiation between overlapping lines due to different crystallographic sites and also different isotopes can be achieved. In addition, methods for selective measurements of the spin-spin and spin-lattice relaxation are shown.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
New double resonance techniques for the resolution enhancement of nuclear magnetic resonance of quadrupolar nuclei are presented which use population transfers between Zeeman levels of a quadrupolar split spin system. Experiments on high temperature superconductors are reported where a differentiation between overlapping lines due to different crystallographic sites and also different isotopes can be achieved. In addition, methods for selective measurements of the spin-spin and spin-lattice relaxation are shown.
127.
Haase, J; Curro, NJ; Stern, R; Slichter, CP
New methods for NMR of cuprate superconductors Journal Article
In: Phys. Rev. Lett., vol. 81, no. 7, pp. 1489–1492, 1998, ISSN: 0031-9007.
@article{Haase1998a,
title = {New methods for NMR of cuprate superconductors},
author = {J Haase and NJ Curro and R Stern and CP Slichter},
doi = {10.1103/PhysRevLett.81.1489},
issn = {0031-9007},
year = {1998},
date = {1998-08-01},
journal = {Phys. Rev. Lett.},
volume = {81},
number = {7},
pages = {1489--1492},
abstract = {New nuclear magnetic resonance (NMR) methods for the investigation of high temperature superconductors are reported which alleviate many of the problems NMR faces in such materials. The methods rely on combining population transfers between quadrupolar split Zeeman levels with ordinary NMR experiments. Spins labeled in this manner can be investigated selectively, e.g., allowing the differentiation between isotopes, crystallographic sites, and misaligned grains. Examples for Cu NMR on YBa2Cu4O8 and La1.85Sr0.15CuO4 are reported. The methods will also be applicable to other areas of solid state NMR.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
New nuclear magnetic resonance (NMR) methods for the investigation of high temperature superconductors are reported which alleviate many of the problems NMR faces in such materials. The methods rely on combining population transfers between quadrupolar split Zeeman levels with ordinary NMR experiments. Spins labeled in this manner can be investigated selectively, e.g., allowing the differentiation between isotopes, crystallographic sites, and misaligned grains. Examples for Cu NMR on YBa2Cu4O8 and La1.85Sr0.15CuO4 are reported. The methods will also be applicable to other areas of solid state NMR.
128.
Stevens, RE; Hsiao, CW; Le, L; Curro, NJ; Monton, BJ; Chang, BY; Kung, CY; Kittrell, C; Kinsey, JL
A partial pressure monitor and controller for stable ozone flow from a silica gel trap Journal Article
In: Rev. Sci. Instrum., vol. 69, no. 6, pp. 2504–2509, 1998, ISSN: 0034-6748.
@article{Stevens1998,
title = {A partial pressure monitor and controller for stable ozone flow from a silica gel trap},
author = {RE Stevens and CW Hsiao and L Le and NJ Curro and BJ Monton and BY Chang and CY Kung and C Kittrell and JL Kinsey},
doi = {10.1063/1.1148950},
issn = {0034-6748},
year = {1998},
date = {1998-06-01},
journal = {Rev. Sci. Instrum.},
volume = {69},
number = {6},
pages = {2504--2509},
abstract = {A new ozone trapping system designed for safe and consistent delivery to a reaction vessel is described. Silica gel is used to trap the ozone because of its known safety advantages over traps that store ozone in liquid form. The new design is free of any liquid baths, such as freon or flammable solvents. A circuit design for monitoring and controlling the ozone partial pressure of 6-25 Torr is also described. (C) 1998 American Institute of Physics. [S0034-6748(98)01006-5]},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
A new ozone trapping system designed for safe and consistent delivery to a reaction vessel is described. Silica gel is used to trap the ozone because of its known safety advantages over traps that store ozone in liquid form. The new design is free of any liquid baths, such as freon or flammable solvents. A circuit design for monitoring and controlling the ozone partial pressure of 6-25 Torr is also described. (C) 1998 American Institute of Physics. [S0034-6748(98)01006-5]
129.
Curro, NJ; Slichter, CP
Contributions of spin-lattice relaxation to the echo decay of planar Cu in high-temperature superconductors Journal Article
In: J. Magn. Reson., vol. 130, no. 2, pp. 186–194, 1998, ISSN: 1090-7807.
@article{Curro1998,
title = {Contributions of spin-lattice relaxation to the echo decay of planar Cu in high-temperature superconductors},
author = {NJ Curro and CP Slichter},
doi = {10.1006/jmre.1997.1295},
issn = {1090-7807},
year = {1998},
date = {1998-02-01},
journal = {J. Magn. Reson.},
volume = {130},
number = {2},
pages = {186--194},
abstract = {Measurement of T-2G, the Gaussian component of the spin-echo envelope of planar Cu nuclei in high-temperature superconductors, gives important information about the real part of the Cu electron spin susceptibility. In the traditional picture of the planar Cu echo decay, the internuclear coupling is assumed to remain static with respect to spin-lattice relaxation and mutual exchange fluctuations. In some circumstances, however, this assumption breaks down. We calculate the internuclear corrections arising from spin-lattice relaxation to the conventional theory of T-2G and show that T-2G can be easily corrected for these effects. We argue that mutual exchanges due to the perpendicular indirect couplings are suppressed in these materials. For YBa2Cu4O8, we iind a correction on the order of 10% in T(2)G and using the corrected values we find that the isotope ratio T-63(2G)/T-65(2G) agrees with theory. (C) 1998 Academic Press.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Measurement of T-2G, the Gaussian component of the spin-echo envelope of planar Cu nuclei in high-temperature superconductors, gives important information about the real part of the Cu electron spin susceptibility. In the traditional picture of the planar Cu echo decay, the internuclear coupling is assumed to remain static with respect to spin-lattice relaxation and mutual exchange fluctuations. In some circumstances, however, this assumption breaks down. We calculate the internuclear corrections arising from spin-lattice relaxation to the conventional theory of T-2G and show that T-2G can be easily corrected for these effects. We argue that mutual exchanges due to the perpendicular indirect couplings are suppressed in these materials. For YBa2Cu4O8, we iind a correction on the order of 10% in T(2)G and using the corrected values we find that the isotope ratio T-63(2G)/T-65(2G) agrees with theory. (C) 1998 Academic Press.
130.
Slichter, C. P.; Corey, R.; Curro, N.; Haase, J.; Milling, C.; Morr, D.; Schmalian, J.; Stern, R.
J-coupling in high temperature superconductors Journal Article
In: Mol. Phys., vol. 95, no. 5, pp. 897–906, 1998, ISSN: 0026-8976.
@article{Slichter1998,
title = {J-coupling in high temperature superconductors},
author = {C. P. Slichter and R. Corey and N. Curro and J. Haase and C. Milling and D. Morr and J. Schmalian and R. Stern},
doi = {10.1080/002689798166521},
issn = {0026-8976},
year = {1998},
date = {1998-01-01},
journal = {Mol. Phys.},
volume = {95},
number = {5},
pages = {897--906},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
131.
Curro, NJ; Imai, T; Slichter, CP; Dabrowski, B
High-temperature $^63$Cu(2) nuclear quadrupole and magnetic resonance measurements of YBa$_2$Cu$_4$O$_8$ Journal Article
In: Phys. Rev. B, vol. 56, no. 2, pp. 877–885, 1997, ISSN: 0163-1829.
@article{Curro1997,
title = {High-temperature $^63$Cu(2) nuclear quadrupole and magnetic resonance measurements of YBa$_2$Cu$_4$O$_8$},
author = {NJ Curro and T Imai and CP Slichter and B Dabrowski},
doi = {10.1103/PhysRevB.56.877},
issn = {0163-1829},
year = {1997},
date = {1997-07-01},
journal = {Phys. Rev. B},
volume = {56},
number = {2},
pages = {877--885},
abstract = {We report data on the Gaussian transverse relaxation rate 1/T-2G, the Knight shift K-s, and the spin-lattice relaxation time T-1, in YBa2Cu4O8 from 100 K up to 715 K, extending the upper temperature of previous studies by 200 K. The T-2G data are corrected for a small spin-lattice fluctuation contribution to the echo decay. Calculations of T1T/T-2G and T1T/T-2G(2) show that there is a crossover in scaling behavior at a temperature T(cr)similar to 500 K; The Knight-shift data also exhibit a maximum at this temperature and decrease slowly with increasing temperature above this. Calculations using an independent form for the susceptibility due to Sokol, Singh, and Elstner suggest that the correlation length for antiferromagnetic fluctuations is on the order of one: to two lattice spacings at this crossover temperature, in agreement with the proposal of Barzykin and Pines.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
We report data on the Gaussian transverse relaxation rate 1/T-2G, the Knight shift K-s, and the spin-lattice relaxation time T-1, in YBa2Cu4O8 from 100 K up to 715 K, extending the upper temperature of previous studies by 200 K. The T-2G data are corrected for a small spin-lattice fluctuation contribution to the echo decay. Calculations of T1T/T-2G and T1T/T-2G(2) show that there is a crossover in scaling behavior at a temperature T(cr)similar to 500 K; The Knight-shift data also exhibit a maximum at this temperature and decrease slowly with increasing temperature above this. Calculations using an independent form for the susceptibility due to Sokol, Singh, and Elstner suggest that the correlation length for antiferromagnetic fluctuations is on the order of one: to two lattice spacings at this crossover temperature, in agreement with the proposal of Barzykin and Pines.
132.
Slichter, CP; Corey, RL; Curro, NJ; DeSoto, SM; OHara, K; Imai, T; Kini, AM; Wang, HH; Geiser, U; Williams, JM; Yoshimura, K; Katoh, M; Kosuge, K
Nuclear magnetic resonance and electron spins: Some history, ancient and in the making Journal Article
In: Phil. Mag. B, vol. 74, no. 5, pp. 545–561, 1996, ISSN: 0141-8637.
@article{Slichter1996,
title = {Nuclear magnetic resonance and electron spins: Some history, ancient and in the making},
author = {CP Slichter and RL Corey and NJ Curro and SM DeSoto and K OHara and T Imai and AM Kini and HH Wang and U Geiser and JM Williams and K Yoshimura and M Katoh and K Kosuge},
doi = {10.1080/01418639608240356},
issn = {0141-8637},
year = {1996},
date = {1996-11-01},
journal = {Phil. Mag. B},
volume = {74},
number = {5},
pages = {545--561},
abstract = {Scaling relationships for NMR spin-lattice reIaxation time T-1 and Gaussian transverse relaxation time T-2G are reviewed and applied to analyse experiments in the normal state of YBa2Cu4O8. Studies of T-2G in the superconducting state are analysed using the theory of Pines and Wrobel to show a preference for d-state orbital pairing over anisotropic s-state. Data on C-13 NMR in the normal and superconducting state of the two dimensional organic conductor (ET)(2)Cu[N(CN)(2)]Br are presented and shown to have great similarity to that of the cuprates.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Scaling relationships for NMR spin-lattice reIaxation time T-1 and Gaussian transverse relaxation time T-2G are reviewed and applied to analyse experiments in the normal state of YBa2Cu4O8. Studies of T-2G in the superconducting state are analysed using the theory of Pines and Wrobel to show a preference for d-state orbital pairing over anisotropic s-state. Data on C-13 NMR in the normal and superconducting state of the two dimensional organic conductor (ET)(2)Cu[N(CN)(2)]Br are presented and shown to have great similarity to that of the cuprates.
133.
Corey, RL; Curro, NJ; OHara, K; Imai, T; Slichter, CP; Yoshimura, K; Katoh, M; Kosuge, K
$^63$Cu(2) nuclear quadrupole and nuclear magnetic resonance studies of YBa$_2$Cu$_4$O$_8$ in the normal and superconducting states Journal Article
In: Phys. Rev. B, vol. 53, no. 9, pp. 5907–5914, 1996, ISSN: 0163-1829.
@article{Corey1996,
title = {$^63$Cu(2) nuclear quadrupole and nuclear magnetic resonance studies of YBa$_2$Cu$_4$O$_8$ in the normal and superconducting states},
author = {RL Corey and NJ Curro and K OHara and T Imai and CP Slichter and K Yoshimura and M Katoh and K Kosuge},
doi = {10.1103/PhysRevB.53.5907},
issn = {0163-1829},
year = {1996},
date = {1996-03-01},
journal = {Phys. Rev. B},
volume = {53},
number = {9},
pages = {5907--5914},
abstract = {We report nuclear quadrupole resonance (NQR) and nuclear magnetic resonance (NMR) measurements of the spin lattice and Gaussian spin-spin relaxation limes, T-1 and T-2G, respectively, in an unaligned (NQR) and aligned (NMR) powder of YBa2Cu4O8 Experimental details, critical for accurate NQR measurements in this system, are discussed. The normal-state data are analyzed using several models. Evidence for the existence of a spin gap is presented. The normal-state data agree well with an analysis using scaling theory predictions for z=1 quantum critical and quantum disordered regimes. The superconducting state data agree with recent calculations for d-wave superconductivity.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
We report nuclear quadrupole resonance (NQR) and nuclear magnetic resonance (NMR) measurements of the spin lattice and Gaussian spin-spin relaxation limes, T-1 and T-2G, respectively, in an unaligned (NQR) and aligned (NMR) powder of YBa2Cu4O8 Experimental details, critical for accurate NQR measurements in this system, are discussed. The normal-state data are analyzed using several models. Evidence for the existence of a spin gap is presented. The normal-state data agree well with an analysis using scaling theory predictions for z=1 quantum critical and quantum disordered regimes. The superconducting state data agree with recent calculations for d-wave superconductivity.
134.
Curro, N. J.; Kissikov, T.; Tanatar, M. A.; Prozorov, R.; Bud'ko, S. L.; Canfield, P. C.
Nematicity and Glassy Behavior Probed by Nuclear Magnetic Resonance in Iron-Based Superconductors Journal Article
In: Frontiers in Physics, vol. 10, pp. 877628, 0000.
@article{Curro2022b,
title = {Nematicity and Glassy Behavior Probed by Nuclear Magnetic Resonance in Iron-Based Superconductors},
author = {N. J. Curro and T. Kissikov and M. A. Tanatar and R. Prozorov and S. L. Bud'ko and P. C. Canfield},
doi = {10.3389/fphy.2022.877628},
journal = {Frontiers in Physics},
volume = {10},
pages = {877628},
keywords = {},
pubstate = {published},
tppubtype = {article}
}