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

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 study of vortex states inRBa2Cu3O7using maximum-entropy analysis

Physical Review B ◽

10.1103/physrevb.49.12396 ◽

1994 ◽

Vol 49 (17) ◽

pp. 12396-12399 ◽

Cited By ~ 9

Author(s):

S. Alves ◽

C. Boekema ◽

C. Halim ◽

J. C. Lam ◽

E. Whang ◽

...

Keyword(s):

Maximum Entropy ◽

Muon Spin ◽

Spin Rotation ◽

Muon Spin Rotation ◽

Entropy Analysis ◽

Vortex States ◽

Rotation Study

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

International Journal of Modern Physics B ◽

10.1142/s0217979215420266 ◽

2015 ◽

Vol 29 (25n26) ◽

pp. 1542026 ◽

Cited By ~ 1

Author(s):

C. Boekema ◽

F. Owens ◽

A. Love ◽

Z. Li ◽

P. Sakkaris ◽

...

Keyword(s):

Muon Spin ◽

Transverse Field ◽

Muon Spin Rotation ◽

Zero Field ◽

Text Data ◽

Fundamental Physics ◽

Site Search ◽

Cuprate Superconductivity ◽

Magnetic Origin ◽

Text Signals

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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