Anisotropy and multiband superconductivity in 
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mrow><mml:mi>Sr</mml:mi></mml:mrow><mml:mn>2</mml:mn></mml:msub><mml:msub><mml:mrow><mml:mi>RuO</mml:mi></mml:mrow><mml:mn>4</mml:mn></mml:msub></mml:math>
 determined by small-angle neutron scattering studies of the vortex lattice

Kuhn, Stephen J.; Morgenlander, William R.; Louden, E. R.; Rastovski, C.; Gannon, W. J.; Takatsu, Hiroshi; Peets, Darren C.; Maeno, Y.; Dewhurst, C. D.; Gavilano, J. L.; Eskildsen, M. R.

doi:10.1103/physrevb.96.174507

Cited by 18 publications

(10 citation statements)

References 79 publications

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“…41(b) (Campbell et al, 1988;Das et al, 2012c;Gammel et al, 1994;Keimer et al, 1993;Yethiraj et al, 1993a). The VL anisotropy Γ VL is given by the major-to-minor axis ratio, and due to flux quantization it is sufficient to measure the location of the VL Bragg peaks along the minor ellipse axis (Kuhn et al, 2017;Rastovski et al, 2013a). For fields parallel to the basal plane Γ VL = Γ ac .…”

Section: Complex Order Parameters Multigap Superconductivity and Paumentioning

confidence: 99%

Magnetic small-angle neutron scattering

et al. 2019

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Small-angle neutron scattering (SANS) is one of the most important techniques for microstructure determination, being utilized in a wide range of scientific disciplines, such as materials science, physics, chemistry, and biology. The reason for its great significance is that conventional SANS is probably the only method capable of probing structural inhomogeneities in the bulk of materials on a mesoscopic real-space length scale, from roughly 1 − 300 nm. Moreover, the exploitation of the spin degree of freedom of the neutron provides SANS with a unique sensitivity to study magnetism and magnetic materials at the nanoscale. As such, magnetic SANS ideally complements more real-space and surface-sensitive magnetic imaging techniques, e.g., Lorentz transmission electron microscopy, electron holography, magnetic force microscopy, Kerr microscopy, or spinpolarized scanning tunneling microscopy. In this review article we summarize the recent applications of the SANS method to study magnetism and magnetic materials. This includes a wide range of materials classes, from nanomagnetic systems such as soft magnetic Fe-based nanocomposites, hard magnetic Nd−Fe−B-based permanent magnets, magnetic steels, ferrofluids, nanoparticles, and magnetic oxides, to more fundamental open issues in contemporary condensed matter physics such as skyrmion crystals, noncollinar magnetic structures in noncentrosymmetric compounds, magnetic/electronic phase separation, and vortex lattices in type-II superconductors. Special attention is paid not only to the vast variety of magnetic materials and problems where SANS has provided direct insight, but also to the enormous progress made regarding the micromagnetic simulation of magnetic neutron scattering.

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Section: Complex Order Parameters Multigap Superconductivity and Paumentioning

confidence: 99%

Magnetic small-angle neutron scattering

et al. 2019

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“…A further puzzle is the anomalous suppression of the in-plane upper critical field H c2 [43] at low temperatures and a related firstorder nature of the superconducting transition [38,44,45]. The suppression of the in-plane H c2 was also implicated in the vortex lattice anisotropy throughout the mixed state [46,47]. These resemble the Pauli limiting behavior, and can usually be tied to spin-singlet pairing, but may also be explained if the d-vector of the spin-triplet pairing lies in the planewhich however corresponds to a time-reversal invariant helical state.…”

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confidence: 99%

Superconducting pairing in Sr2RuO4 from weak to intermediate coupling

et al. 2018

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The unconventional superconductivity in Sr2RuO4 continues to attract considerable interest. While many measurements can be interpreted on the basis of chiral p-wave pairing with intriguing topological character, a number of exceptions hinder an unambiguous verification of such pairing. The pairing mechanism also remains under debate. In this paper, with effects of the sizable spin-orbit coupling accounted for, we reexamine the superconducting instabilities in Sr2RuO4 through systematic microscopic analysis within random phase approximation. Our calculations show that the odd-parity p-wave pairing is favored in the regime of extremely weak interactions, but that highly anisotropic even-parity pairings become most leading over a broad range of stronger interactions. These results could shed light on the nature of the enigmatic superconductivity in Sr2RuO4.The superconductivity in Sr 2 RuO 4 has attracted significant attention since it was discovered in 1994 [1][2][3]. The discovery was followed by proposals of p-wave pairing arising from possible remnant ferromagnetic correlations in the material [4][5][6], which was later substantiated by experimental evidences of spin-triplet and odd-parity pairing [7][8][9][10][11]. The observation of time-reversal symmetry breaking [12,13] raised the prospect of topological chiral p-wave pairing which supports Majorana fermions [14,15]. However, despite many progresses, the chiral p-wave order has not been fully established, largely due to the difficulties in reconciling it with a variety of other measurements [16][17][18][19]. We highlight some major issues below.A major prediction for chiral p-wave is the appearance of spontaneous chiral currents at the edges and domain walls separating regions of opposite chiralities [20,21]. However, no clear signature of chiral current have been detected so far [22][23][24]. We stress that, as the current is not topologically protected [25], it can be suppressed, to various degrees, by gap and band structure anisotropy, surface disorder and the multiband effects [25][26][27][28][29][30][31]. However, acquiring full consistency with the experimental null result in the best prepared sample/device is perhaps only possible with a fine-tuned gap structure. Remarkably, edge current could vanish in non-pwave chiral superconductors such as chiral dand f -wave, etc [32][33][34][35]. Yet these states may be less likely in Sr 2 RuO 4 [32].Another discrepancy is the absence of split transitions when an in-plane magnetic field or a uniaxial strain breaks the degeneracy between the two chiral components [36][37][38][39][40][41][42]. A further puzzle is the anomalous suppression of the in-plane upper critical field H c2 [43] at low temperatures and a related firstorder nature of the superconducting transition [38,44,45]. The suppression of the in-plane H c2 was also implicated in the vortex lattice anisotropy throughout the mixed state [46,47]. These resemble the Pauli limiting behavior, and can usually be tied to spin-singlet pairing, but may also be ex...

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“…41(b) (Campbell, Doria, and Kogan, 1988;Keimer et al, 1993;Yethiraj et al, 1993a;Gammel et al, 1994;. The VL anisotropy Γ VL is given by the major-to-minor axis ratio, and due to flux quantization it is sufficient to measure the location of the VL Bragg peaks along the minor ellipse axis (Rastovski, Dewhurst et al, 2013;Kuhn et al, 2017). For fields parallel to the basal plane Γ VL ¼ Γ ac .…”

Section: Complex Order Parameters Multigap Superconductivity and Pauli Limitingmentioning

confidence: 99%

Magnetic Small-Angle Neutron Scattering

Michels

2021

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This book provides the first extensive treatment of magnetic small-angle neutron scattering (SANS). The theoretical background required to compute magnetic SANS cross sections and correlation functions related to long-wavelength magnetization structures is laid out; and these concepts are scrutinized based on the discussion of experimental neutron data. Regarding prior background knowledge, some familiarity with the basic magnetic interactions and phenomena, as well as scattering theory, is desired. The target audience comprises Ph.D. students and researchers working in the field of magnetism and magnetic materials who wish to make efficient use of the magnetic SANS method. Besides revealing the origins of magnetic SANS (Chapter 1), and furnishing the basics of the magnetic SANS technique (Chapter 2), much of the book is devoted to a comprehensive treatment of the continuum theory of micromagnetics (Chapter 3), as it is relevant for the study of the elastic magnetic SANS cross section. Analytical expressions for the magnetization Fourier components allow one to highlight the essential features of magnetic SANS and to analyze experimental data both in reciprocal (Chapter 4) and real space (Chapter 6). Chapter 5 provides an overview of the magnetic SANS of nanoparticles and so-called complex systems (e.g., ferrofluids, magnetic steels, spin glasses, and amorphous magnets). It is this subfield where major progress is expected to be made in the coming years, mainly via the increased use of numerical micromagnetic simulations (Chapter 7), which is a very promising approach for the understanding of the magnetic SANS from systems exhibiting nanoscale spin inhomogeneity.

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Anisotropy and multiband superconductivity in Sr2RuO4 determined by small-angle neutron scattering studies of the vortex lattice

Cited by 18 publications

References 79 publications

Magnetic small-angle neutron scattering

Magnetic small-angle neutron scattering

Superconducting pairing in Sr2RuO4 from weak to intermediate coupling

Magnetic Small-Angle Neutron Scattering

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