A magnetic origin of cuprate superconductivity? A MaxEnt-μSR view

The fundamental physics of cuprate superconductivity is still much deliberated after three decades of research. In contrast to phononic or polaronic roots, some major theories promote a magnetic origin. In this perspective, we review cuprate magnetism, as probed by muon-spin-rotation [Formula: see text] in [Formula: see text] (RBCO), [Formula: see text] (Bi2212) and [Formula: see text] (Tl2223). Site-search RBCO studies show that muons localize and probe in locations away from the superconducting CuO2 planes. Maximum entropy (MaxEnt, ME) analysis of transverse field [Formula: see text] data of [Formula: see text] (GdBCO) indicates that the muon probes in an undisturbed insulating environment, allowing [Formula: see text] to detect (weak) magnetic features in these cuprates. Concerning Varma’s predicted loop currents, MaxEnt has shown weak [Formula: see text] signals for GdBCO in zero field above and below the critical temperature, [Formula: see text]; these are near the predicted [Formula: see text] Oe. Concerning Zhang’s predicted antiferromagnetism (AF) connected to the vortex cores, we have observed Lorentzian relaxation of cuprate vortex signals below half [Formula: see text], consistent with AF-broadening effects. For both Bi2212 and Tl2223, Lorentzians describe the [Formula: see text] vortex signals much better below [Formula: see text] than Gaussians, indicating that extra AF fields occur near and in the vortex cores. In sum, both our MaxEnt-[Formula: see text] (ME-[Formula: see text]) studies point toward magnetic roots of cuprate superconductivity.

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Plausiblity of Antiferromagnetism in and near RBCO Vortex Cores: An ME-μSR Analysis

International Journal of Modern Physics B ◽

10.1142/s0217979203021150 ◽

2003 ◽

Vol 17 (18n20) ◽

pp. 3436-3440 ◽

Cited By ~ 6

Author(s):

C. Boekema ◽

Y. Tien ◽

L. Hughes ◽

E. J. Ruiz ◽

S. X. Cavanaugh

Keyword(s):

Grain Boundary ◽

Maximum Entropy ◽

Vortex Core ◽

Muon Spin ◽

Spin Rotation ◽

Muon Spin Rotation ◽

Vortex States ◽

Search Results ◽

Cuprate Superconductivity ◽

Magnetic Origin

Maximum-Entropy (ME) analysis is applied to muon-spin-rotation (μSR) data of RBa 2 Cu 3 O y (RBCO; R = Ho , Eu) vortex states. Our focus is on the prospect of antiferromagnetism (AF) associated with the vortex core. The ME transforms are fitted by two μSR signals: the vortex signal and the grain-boundary (GB) signal. Below Tc, the GB signals are well fitted by Gaussians for both EuBCO (Tc = 94 K ) and underdoped HoBCO (Tc = 66 K ). Below 0.5Tc, EuBCO and HoBCO vortex signals are best fitted using Lorentzians, instead of expected Gaussians. An estimate for an effective Neél temperature of an AF vortex core is about 30 K. Our AF-core search results for RBCO vortex states are discussed considering a magnetic origin of cuprate superconductivity.

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Muon spin rotation and relaxation study on topological noncentrosymmetric superconductor PbTaSe2

New Journal of Physics ◽

10.1088/1367-2630/ac48ea ◽

2022 ◽

Author(s):

Zihao Zhu ◽

Cheng Tan ◽

Jian Zhang ◽

Pabitra Kumar Biswas ◽

A D Hillier ◽

...

Keyword(s):

Energy Gap ◽

Muon Spin ◽

Three Dimensional ◽

Transverse Field ◽

Muon Spin Rotation ◽

Zero Field ◽

Noncentrosymmetric Superconductor ◽

Topological Surface ◽

Symmetry Protected ◽

Topological Superconductivity

Abstract Topological superconductivity is an exotic phenomenon due to the symmetry-protected topological surface state, in which a quantum system has an energy gap in the bulk but supports gapless excitations conned to its boundary. Symmetries including central and time-reversal, along with their relations with topology, are crucial for topological superconductivity. We report muon spin relaxation/rotation (μSR) experiments on a topological noncentrosymmetric superconductor PbTaSe2 to study its TRS and gap symmetry. Zero-field μSR experiments indicate the absence of internal magnetic eld in the superconducting state, consistent with previous μSR results. Furthermore, transverse-field μSR measurements reveals that the superconducting gap of PbTaSe2 is an isotropic three-dimensional fully-gapped single-band. The fully-gapped results can help understand the pairing mechanism and further classify the topological superconductivity in this system.

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On the Robustness of the MnSi Magnetic Structure Determined by Muon Spin Rotation

Quantum Beam Science ◽

10.3390/qubs2030019 ◽

2018 ◽

Vol 2 (3) ◽

pp. 19 ◽

Cited By ~ 3

Author(s):

Pierre Dalmas de Réotier ◽

Alain Yaouanc ◽

Alex Amato ◽

Alexander Maisuradze ◽

Daniel Andreica ◽

...

Keyword(s):

Magnetic Structure ◽

Muon Spin ◽

Transverse Field ◽

Spin Rotation ◽

Muon Spin Rotation ◽

Zero Field ◽

Magnetic Structures ◽

Wide Range ◽

Distribution Parameters ◽

Manganese Silicide

Muon spin rotation ( μ SR) spectra recorded for manganese silicide MnSi and interpreted in terms of a quantitative analysis constrained by symmetry arguments were recently published. The magnetic structures of MnSi in zero-field at low temperature and in the conical phase near the magnetic phase transition were shown to substantially deviate from the expected helical and conical structures. Here, we present material backing the previous results obtained in zero-field. First, from simulations of the field distributions experienced by the muons as a function of relevant parameters, we confirm the uniqueness of the initial interpretation and illustrate the remarkable complementarity of neutron scattering and μ SR for the MnSi magnetic structure determination. Second, we present the result of a μ SR experiment performed on MnSi crystallites grown in a Zn-flux and compare it with the previous data recorded with a crystal obtained from Czochralski pulling. We find the magnetic structure for the two types of crystals to be identical within experimental uncertainties. We finally address the question of a possible muon-induced effect by presenting transverse field μ SR spectra recorded in a wide range of temperature and field intensity. The field distribution parameters perfectly scale with the macroscopic magnetization, ruling out a muon-induced effect.

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MUON SPIN ROTATION IN SR2YRU1-UCUUO6

International Journal of Modern Physics B ◽

10.1142/s0217979299003647 ◽

1999 ◽

Vol 13 (29n31) ◽

pp. 3670-3677 ◽

Cited By ~ 16

Author(s):

D. R. HARSHMAN ◽

H. A. BLACKSTEAD ◽

W. J. KOSSLER ◽

A. J. GREER ◽

C. E. STRONACH ◽

...

Keyword(s):

Field Data ◽

Muon Spin ◽

Magnetic Moments ◽

Transverse Field ◽

Sudden Onset ◽

Spin Rotation ◽

Muon Spin Rotation ◽

Zero Field ◽

Slow Dynamic ◽

Oxygen Ions

The magnetic and superconducting behaviors of sintered Sr 2 YRu 1-u Cu u O 6 (for u=0.05, 0.10, 0.15) were probed using transverse- and zero-field muon spin rotation (μ+ SR). In general, positive muons are attracted to oxygen ions in the high-T c oxides, and so, Sr 2 YRu 1-u Cu u O 6 should (and does) present two types of μ+ sites, those associated with the oxygen in the YRuO 4 layers and those associated with the SrO-layer oxygen. The tranverse- and zero-field data for all three stoichiometries u exhibit a sudden onset of magnetic structure at TN~30 K, with a static local field of ~3 kG. This transition is marked by a dramatic increase in the relaxation rate as the temperature decreases below TN, corresponding to an increased static disordering of the magnetic moments. Above TN no static fields are observed. Instead the data exhibit a slow dynamic depolarization, presumably due to the rapid fluctuation of paramagnetic moments. Both transverse- and zero-field data also indicate a smaller second component (~10%) which we associate with the SrO layer, exhibiting superconducting behavior in transverse field with an observed T c ≈TN~30 K.

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Zero-Field Muon Spin Rotation Studies in (TMTSF) 2 PF 6

EPL (Europhysics Letters) ◽

10.1209/0295-5075/15/5/013 ◽

1991 ◽

Vol 15 (5) ◽

pp. 547-552 ◽

Cited By ~ 27

Author(s):

L. P Le ◽

G. M Luke ◽

B. J Sternlieb ◽

W. D Wu ◽

Y. J Uemura ◽

...

Keyword(s):

Muon Spin ◽

Spin Rotation ◽

Muon Spin Rotation ◽

Zero Field

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Two-gap superconductivity in Lu2Fe3Si5: A transverse-field muon spin rotation study

Physical Review B ◽

10.1103/physrevb.83.054517 ◽

2011 ◽

Vol 83 (5) ◽

Cited By ~ 11

Author(s):

P. K. Biswas ◽

G. Balakrishnan ◽

D. McK. Paul ◽

M. R. Lees ◽

A. D. Hillier

Keyword(s):

Muon Spin ◽

Transverse Field ◽

Spin Rotation ◽

Muon Spin Rotation ◽

Rotation Study

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Transverse field muon-spin rotation signature of the skyrmion-lattice phase inCu2OSeO3

Physical Review B ◽

10.1103/physrevb.91.224408 ◽

2015 ◽

Vol 91 (22) ◽

Cited By ~ 14

Author(s):

T. Lancaster ◽

R. C. Williams ◽

I. O. Thomas ◽

F. Xiao ◽

F. L. Pratt ◽

...

Keyword(s):

Muon Spin ◽

Transverse Field ◽

Spin Rotation ◽

Muon Spin Rotation

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Radical addition to ruthenocene at low temperatures: characterization of ruthenocenyl radicals by μSR spectroscopy

Canadian Journal of Chemistry ◽

10.1139/cjc-2017-0207 ◽

2018 ◽

Vol 96 (3) ◽

pp. 358-362 ◽

Cited By ~ 3

Author(s):

Iain McKenzie

Keyword(s):

Dft Calculations ◽

Spin Relaxation ◽

Muon Spin ◽

Transverse Field ◽

Relaxation Mechanism ◽

Coupling Constants ◽

Muon Spin Rotation ◽

Electron Spin Relaxation ◽

Spin Resonance ◽

Experimental Values

The radicals formed by muonium (Mu) addition to ruthenocene at low temperature (4–200 K) have been characterized by transverse field muon spin rotation (TF-μSR) and avoided level crossing muon spin resonance (ALC-μSR) spectroscopy. The structures of the muoniated radicals have been identified by comparing the experimentally measured muon hyperfine coupling constants with values obtained from DFT calculations (UB3LYP/DGDZVP). Mu addition was observed at the ruthenium and at the cyclopentadiene (Cp) rings, both from the exterior and interior directions. Closer agreement between the DFT calculations and the experimental values are obtained if it is assumed the structures of the Mu adducts of the Cp rings are distorted due to interactions with neighbouring molecules. Changes in the ALC-μSR spectra with temperature indicated that the electron spin relaxation rate of the Cp adducts increases with temperature; however, the specific spin relaxation mechanism is unknown.

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