Point-contact study of the magnetic superconductor HoNi2B2C

Rybaltchenko, L. F.; Jansen, A. G. M.; Wyder, P.; Tjutrina, L.V.; Canfield, Paul C.; Tomy, C. V.; Paul, D. McK.

doi:10.1016/s0921-4534(99)00282-8

Cited by 19 publications

(21 citation statements)

References 21 publications

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“…In contrast to the PC data reported in Ref. 12, where ∆ initially increases (∼ 10%) in magnetic fields before it drops off to zero, in our case ∆(B) exhibits a conventional behavior. decreasing with overall negative curvature (see Fig.…”

Section: Pcs Of the Sc Energy Gap In The Commensurate Antiferromagnetcontrasting

confidence: 99%

“…This observation together with analogous data for ∆ from [11,12] both for poly-and single HoNi 2 B 2 C crystals demonstrates at least a small gap anisotropy and a reasonable physical meaning of T * c . Therefore we adopt the "Fermi surface separation" scenario for the coexistence of magnetism and superconductivity in magnetic borocarbides, i.e.…”

Section: Pcs Of the Sc Energy Gap In The Commensurate Antiferromagnetsupporting

confidence: 72%

“…Up to now, HoNi 2 B 2 C has been investigated by PC spectroscopy in [11,12,13,14]. The first three papers are devoted to investigations of the SC gap.…”

Section: Introductionmentioning

confidence: 99%

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Point-contact spectroscopy of the antiferromagnetic superconductorHoNi2B2Cin the normal and superconducting state

et al. 2007

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Point-contact (PC) spectroscopy measurements on antiferromagnetic (AF) (TN ≃5.2 K) HoNi2B2C single crystals in the normal and two different superconducting (SC) states (Tc ≃8.5 K and T * c ≃ 5.6 K) are reported. The PC study of the electron-boson(phonon) interaction (EB(P)I) spectral function reveals pronounced phonon maxima at 16, 22 and 34 meV. For the first time the high energy maxima at about 50 meV and 100 meV are resolved. Additionally, an admixture of a crystalline-electric-field (CEF) excitations with a maximum near 10 meV and a 'magnetic' peak near 3 meV are observed. The contribution of the 10-meV peak in PC EPI constant λPC is evaluated as 20-30%, while contribution of the high energy modes at 50 and 100 meV amounts about 10% for each maxima, so the superconductivity might be affected by CEF excitations. The SC gap in HoNi2B2C exhibits a standard single-band BCS-like dependence, but vanishes at T * c ≃ 5.6 K< Tc, with 2∆/kBT * c ≃ 3.9. The strong coupling Eliashberg analysis of the low-temperature SC phase with T * c ≃ 5.6 K ∼ TN, coexisting with the commensurate AF structure, suggests a sizable value of the EPI constant λs ∼ 0.93. We also provide strong support for the recently proposed by us "Fermi surface (FS) separation" scenario for the coexistence of magnetism and superconductivity in magnetic borocarbides, namely, that the superconductivity in the commensurate AF phase survives at a special (nearly isotropic) FS sheet without an admixture of Ho 5d states. Above T * c the SC features in the PC characteristics are strongly suppressed pointing to a specific weakened SC state between T * c and Tc.

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Section: Pcs Of the Sc Energy Gap In The Commensurate Antiferromagnetcontrasting

confidence: 99%

Section: Pcs Of the Sc Energy Gap In The Commensurate Antiferromagnetsupporting

confidence: 72%

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Point-contact spectroscopy of the antiferromagnetic superconductorHoNi2B2Cin the normal and superconducting state

et al. 2007

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“…Both types of data, obtained in the same experiment, unambiguously confirm the occurrence of the superconductivity enhancement effect. Earlier, enhancement of superconductivity in magnetic field was detected in HoNi 2 B 2 C magnetic superconductor [13] and in high-T c materials with magnetic impurities [14]. Probably, all these results are attributed to the reduction of the spin-disorder scattering due to the spin alignment improvement in an applied weak magnetic field as it was discussed in [13].…”

mentioning

confidence: 85%

“…Earlier, enhancement of superconductivity in magnetic field was detected in HoNi 2 B 2 C magnetic superconductor [13] and in high-T c materials with magnetic impurities [14]. Probably, all these results are attributed to the reduction of the spin-disorder scattering due to the spin alignment improvement in an applied weak magnetic field as it was discussed in [13]. Moreover, existence of the negative magnetoresistance in ReM 4 Al 8 compounds in a weak magnetic fields at temperatures just before the superconducting transition [7,8] supports this suggestion.…”

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confidence: 95%

Direct evidence for the occurrence of superconductivity in the magnetic compound YFe4Al8

Dmitriev

Rybaltchenko

Wyder

et al. 2002

Low Temperature Physics

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For the first time we present the direct evidence for superconductivity in the ternary magnetic compound YFe 4 Al 8 with the ThMn 12 type structure found via point-contact (PC) experiments on contacts between silver needle and single-crystal YFe 4 Al 8 , revealing the distinct Andreev-reflection current. The spectra measured prove the existence of normal-superconducting interface and exhibit the triangular-like shape in a vicinity of zero-bias voltage, inferring the unconventional type of superconductivity. The derived dependences of the order parameter versus temperature ∆(T) and magnetic field ∆(H) are presented. ∆(T) follows BCS theory, whereas ∆(H) do not satisfy any theoretical predictions. In some cases there exists noticeable superconductivity enhancement by a weak magnetic field. The data obtained imply the very inhomogeneous distribution of superconductivity over the sample volume in spite of its single crystal structure. We assume that the reason is associated with inherent magnetic inhomogeneities of this material. The highest values for the critical temperature T c , upper critical magnetic field H c2 , and ratio 2∆(0)/kT c are 7.4 K, 5 T, and 7.2, respectively. [3]. In this work we give, for the first time, the direct evidence for the existence of superconductivity in the rare-earth ternary magnetic compound YFe 4 Al 8 in an Andreevreflection experiment.The family of ternary magnetic compounds ReM 4 Al 8 (Re is a rare earth, M is a transition metal) with the ThMn 12 type structure is known for about two decade and their physical properties have been investigated extensively [4][5][6]. However, weak signs of superconductivity in some of the compounds belonging to this family were discovered only recently in the radio-frequency impedance and heat capacity experiments [7,8]. This is very surprising, because the compounds of this type have a

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Interplay Between Helicoidal Magnetic Ordering and Superconductivity on the Differential Conductance in HoNi2B2C/Ag Junctions

Askerzade

Physics of Spin in Solids: Materials, Methods and Applications

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Point-contact study of the magnetic superconductor HoNi2B2C

Cited by 19 publications

References 21 publications

Point-contact spectroscopy of the antiferromagnetic superconductorHoNi2B2Cin the normal and superconducting state

Point-contact spectroscopy of the antiferromagnetic superconductorHoNi2B2Cin the normal and superconducting state

Direct evidence for the occurrence of superconductivity in the magnetic compound YFe4Al8

Interplay Between Helicoidal Magnetic Ordering and Superconductivity on the Differential Conductance in HoNi2B2C/Ag Junctions

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