Elastic Anomalies and Acoustic de Haas-van Alphen Effects in Sr2RuO4

Matsui, Hiroshi; Yamaguchi, M.; Yoshida, Yoshiyuki; Mukai, Atsushi; Settai, Rikio; Ōnuki, Yoshichika; Takei, Hiroyuki; Toyota, Naoki

doi:10.1143/jpsj.67.3687

Cited by 16 publications

(11 citation statements)

References 25 publications

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“…For this reason, we had to analyze the literature data obtained at the same temperature as that of our measurements, 0.4 K, by different groups on a number of various quality crystals. 7,12,30,31 As it was expected, this analysis showed a linear dependence ͉H c2ʈab ͑T , T c ͉͒ T=0.4 K ͑see Fig. 5͒.…”

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confidence: 77%

Influence of hydrostatic pressure on the magnetic phase diagram of superconductingSr2RuO4by ultrasonic attenuation

et al. 2008

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The effect of high hydrostatic pressure on the magnetic field and temperature dependence of the attenuation of a longitudinal ultrasonic wave propagated along the ͗100͘ direction in superconducting Sr 2 RuO 4 has been investigated. The magnetic field dependence of the attenuation suggests the vertical character of the nodes in the superconducting gap. Application of pressure causes a decrease of the critical temperature T c and critical magnetic field H c2 ; the width of the transition under pressure increases. The dependence of H c2ʈab on T c was found to be linear, in contrast to the quadratic one for H c2ʈc . The slope dH c2ʈab / dT c has a universal character; its value does not depend on the physical factor causing reduction of T c , regardless if it is pressure or impurities. The observed effects demonstrate that the pressure application induces an increase in the electronelectron interaction. We show that this increase can be described in terms of a changing electron relaxation time, as in the case of impurities.The persistent interest in layered Sr 2 RuO 4 over the past dozen of years ͑for review see Refs. 1-3͒ is fueled by the unconventional spin-triplet superconductivity 4 and the rich variety of phenomena, related to this property. Some characteristics of this material, for example, two dimensionality of the electron liquid 5 and the Fermi surface topology, 6 have already been understood. At the same time, there is still no self-consistent superconductivity model for this material. In particular, the question of the gap structure is especially contradictory. Some authors believed that the best explanation of experimental results can be achieved with the assumption of vertical nodes. 7-11 Others insist that the assumption of horizontal nodes is more correct and promising. 1,12-19 There have also been suggestions of point nodes. 20 Observation of a second superconducting phase 21 makes this problem even more complicated. The lack of relevant experimental data, in particular, magnetoacoustic and high pressure, was discussed, for example, in Refs. 1, 22, and 23. Consequently, there is a clear motivation to perform more work on Sr 2 RuO 4 , diversifying the experimental techniques and conditions in an effort to obtain deeper insight into the nature of its superconductivity. We believe that our research is an important step in clarifying the gap node character. Among the other revealed phenomena, the linear dependence of the upper critical magnetic field, H c2ʈab , on T c is the most interesting one, especially that it is contrasting with the known 24 quadratic dependence for H c2ʈc .The Sr 2 RuO 4 single crystal was grown by the floating zone technique 25 in oxygen-reduced atmosphere at the rate of 30 mm/ h. The as-grown crystal was about 30 mm in length and 4 mm in diameter. Upon 100 h of annealing at 1000°C in O 2 atmosphere, the crystal was oriented and cut perpendicular to the ͗100͘ direction. The superconducting transition occurred at a temperature of T c = 1.2 K, which indicates the good quality of th...

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confidence: 77%

Influence of hydrostatic pressure on the magnetic phase diagram of superconductingSr2RuO4by ultrasonic attenuation

et al. 2008

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“…Previous bulk measurements of ac susceptibility with strain applied along the 100 direction yielded a ∼ 6 K/% 2 , 16,17,28 and measurements of the jump in ultrasound velocity at the superconducting transition yielded ∼ 5 − 7 K/% 2 . 30 When stress was applied along a 110 direction, on the other hand, the quadratic term was much weaker and a linear coefficient of b ∼ 125 mK/% was measured. 21 The elastic moduli of Sr 2 RuO 4 do not have strong in-plane anisotropy, 31 so pressure along 100 and 110 will yield similar xx + yy and zz strains.…”

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confidence: 99%

Micron-scale measurements of low anisotropic strain response of local Tc in Sr2RuO4

et al. 2018

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Strontium ruthenate (Sr 2 RuO 4 ) is a multiband superconductor that displays evidence of topological superconductivity, although a model of the order parameter that is consistent with all experiments remains elusive. We integrated a piezoelectric-based strain apparatus with a scanning superconducting quantum interference device (SQUID) microscope to map the diamagnetic response of single-crystal Sr 2 RuO 4 as a function of temperature, uniaxial pressure, and position with micron-scale spatial resolution. We thereby obtained local measurements of the superconducting transition temperature T c vs. anisotropic strain with sufficient sensitivity for comparison to theoretical models that assume a uniform p x ± ip y order parameter. We found that T c varies with position and that the locally measured T c vs. curves are quadratic (T c ∝ 2 ), as allowed by the C 4 symmetry of the crystal lattice. We did not observe the low-strain linear cusp (T c ∝ | |) that would be expected for a two-component order parameter such as p x ± ip y . These results provide new input for models of the order parameter of Sr 2 RuO 4 .

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“…4 On the other hand, a large temperature dependence is found in the longitudinal mode C 11 , which is reducible to A 1g and B 1g . With this indication that the B 1g strain ⑀ xx Ϫ⑀ yy might strongly couple to the superconductivity, we have measured the ultrasound velocity and attenuation of (C 11 ϪC 12 )/2 mode to clarify the superconducting order parameter and the collective mode.…”

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confidence: 96%

“…There exist three cylindrical Fermi surfaces named ␣, ␤, and ␥ running along ͓001͔ in a tetragonal structure. [2][3][4] The nuclear relaxation rate T 1 measured by 101 Ru nuclear quadrupole resonance ͑NQR͒ never exhibits a Hebel-Slichter coherence peak, and the Knight shift of 17 O nuclear magnetic resonance ͑NMR͒ 5 is temperature independent below and above T c . The muon spin relaxation indicates a broken time-reversal symmetry in the superconducting state.…”

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Ultrasonic studies of the spin-triplet order parameter and the collective mode inSr2RuO4

et al. 2001

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The elastic constant C T and ultrasonic attenuation ␣ s for (C 11 ϪC 12 )/2 have been measured on Sr 2 RuO 4 with T c *ϭ1.42 K. In contrast to the A 1g and E g strains, the B 1g strain (⑀ xx Ϫ⑀ yy ) strongly couples to the superconducting state, which dominantly originate from hybridized Ru-4d xy electrons on the ␥ Fermi surface. Taken into account impurity induced in-gap states, the T 3 dependence of ␣ s is found to be consistent with an existence of line nodes. The large reduction in C T below T c * evidences the two-component order parameter and chiral p-wave state. Anomalous C T and ␣ s around T a ϭ1.34 K suggest a collective mode.

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Elastic Anomalies and Acoustic de Haas-van Alphen Effects in Sr₂RuO₄

Cited by 16 publications

References 25 publications

Influence of hydrostatic pressure on the magnetic phase diagram of superconductingSr2RuO4by ultrasonic attenuation

Influence of hydrostatic pressure on the magnetic phase diagram of superconductingSr2RuO4by ultrasonic attenuation

Micron-scale measurements of low anisotropic strain response of local Tc in Sr2RuO4

Ultrasonic studies of the spin-triplet order parameter and the collective mode inSr2RuO4

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