Critical current density, vortex dynamics, and phase diagram of single-crystal FeSe

Sun, Yue; Pyon, Sunseng; Tamegai, T.; Kobayashi, Ryota; Watashige, Tatsuya; Kasahara, S.; Matsuda, Yuji; Shibauchi, T.

doi:10.1103/physrevb.92.144509

Cited by 72 publications

(88 citation statements)

References 49 publications

(95 reference statements)

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“…4(a)-(c), respectively. The parameter M * is selected as the maximum value of the magnetization, and the H * is the irreversibility field obtained by extrapolating J c to zero in J 1/2 c vs H curves [35]. For the pristine crystal, the MHLs measured at different temperatures can be well scaled, which is consistent with our previous report that FeSe is dominated by sparse, strong point-like pinning from nanometer-sized defects or imperfections [35].…”

Section: Methodssupporting

confidence: 82%

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Effects of heavy-ion irradiation on FeSe

et al. 2017

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We report the effects of heavy-ion irradiation on FeSe single crystals by irradiating Uranium up to a dose equivalent matching field of B φ = 16 T. Almost continuous columnar defects along the c-axis with a diameter ∼10 nm are confirmed by high-resolution transmission electron microscopy. Tc is found to be suppressed by introducing columnar defects at a rate of dTc/dB φ ∼ -0.29KT −1 , which is much larger than those observed in iron pnictides. This unexpected large suppression of Tc in FeSe is discussed in relation to the large diameter of the columnar defects as well as its unique band structure with a remarkably small Fermi energy. The critical current density is first dramatically enhanced with irradiation reaching a value over ∼2×10 5 A/cm 2 (∼5 times larger than that of the pristine sample) at 2 K (self-field) with B φ = 2 T, then gradually suppressed with increasing B φ . The δl-pinning associated with charge-carrier mean free path fluctuations, and the δTc-pinning associated with spatial fluctuations of the transition temperature are found to coexist in the pristine FeSe, while the irradiation increases the contribution from δl-pinning, and makes it dominant over B φ = 4 T.

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Section: Methodssupporting

confidence: 82%

“…The obtained crystals are of high quality with a sharp superconducting transition width ∆T c < 0.5 K from susceptibility measurements, and large residual resistivity ratio (RRR) ∼33 as reported in our previous publications [6,35].…”

Section: Methodssupporting

confidence: 73%

Effects of heavy-ion irradiation on FeSe

et al. 2017

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“…8,23 , where the data for FeSe was extracted from S(H) at different temperatures 9 and we measured Rb0.8Fe1.6SeS 41 . All previous studies of creep in Fe-SCs have been performed on single crystals [5][6][7][8]14,19,22,23,32,[42][43][44] , where self-fields (Hsf ∝ Jc × thickness) are higher than in our films.…”

Section: S(t) Data From Ybco Samples With Different Microstructures (mentioning

confidence: 99%

Universal lower limit on vortex creep in superconductors

et al. 2017

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The search for a universal description of vortex matter -one that is applicable to a range of systems and regimes -is a formidable challenge, complicated by the complexity of the interactions between vortices and the environment. Vortex motion that can be induced by Magnus and Lorentz forces or thermal activation can also be counteracted by pinning forces. Because vortex cores are normal (i.e., superfluidity or superconductivity is destroyed inside them), creating a vortex costs energy, and pinning can occur when it is energetically more favorable for a vortex to appear in one location than in another. In type-II superconductors at high enough magnetic fields, vortices are formed by the penetration of magnetic flux, and material disorder that locally reduces the vortex core energy can produce pinning forces that almost completely preclude vortex motion. This results in nearly zero resistance, as long as the current density (J) does not exceed the critical current density (Jc). The caveat is that, for J

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“…However, its contribution to the flux creep mechanism has not been previously discussed. According to reference [14], the vortex dynamics in β-FeSe single crystals is governed by a combination of random disorder assisted by a small density of nanometric defects.…”

Section: Introductionmentioning

confidence: 99%

Vortex dynamics inβ-FeSe single crystals: effects of proton irradiation and small inhomogeneous stress

Amigó¹,

Haberkorn²,

Pérez³

et al. 2017

Supercond. Sci. Technol.

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Abstract.We report on the critical current density Jc and the vortex dynamics of pristine and 3 MeV proton irradiated (cumulative dose equal to 2×10 16 cm −2 ) β-FeSe single crystals.We also analyze a remarkable dependence of the superconducting critical temperature Tc, Jc and the flux creep rate S on the sample mounting method. Free-standing crystals present Tc=8.4(1)K, which increases to 10.5(1)K when they are fixed to the sample holder by embedding them with GE-7031 varnish. On the other hand, the irradiation has a marginal effect on Tc. The pinning scenario can be ascribed to twin boundaries and random point defects. We find that the main effect of irradiation is to increase the density of random point defects, while the embedding mainly reduces the density of twin boundaries. Pristine and irradiated crystals present two outstanding features in the temperature dependence of the flux creep rate: S(T ) presents large values at low temperatures, which can be attributed to small pinning energies, and a plateau at intermediate temperatures, which can be associated with glassy relaxation. From Maley analysis, we observe that the characteristic glassy exponent µ changes from ∼ 1.7 to 1.35-1.4 after proton irradiation.

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Critical current density, vortex dynamics, and phase diagram of single-crystal FeSe

Cited by 72 publications

References 49 publications

Effects of heavy-ion irradiation on FeSe

Effects of heavy-ion irradiation on FeSe

Universal lower limit on vortex creep in superconductors

Vortex dynamics inβ-FeSe single crystals: effects of proton irradiation and small inhomogeneous stress

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