Temperature and angular dependence of the upper critical field of UPd2Al3 thin films

Hessert, J.; Huth, Michael; Jourdan, Martin; Adrian, H.; Rieck, C. T.; Scharnberg, K.

doi:10.1016/s0921-4526(96)00725-9

Cited by 19 publications

(14 citation statements)

References 8 publications

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“…In particular, the NMR relaxation rate T −1 1 , which exhibits a T 3 behavior in the superconducting state over four orders of magnitude down to 0.1T c , along with the absence of the Hebel-Slichter coherence peak, indicate the existence of line nodes in the gap function [17]. Pauli limiting H c2 [18], NMR Knight shift reduction [17], and µSR reduction in spin susceptibility [19] below T c favors a spin singlet state. Thus spin-singlet superconducting symmetry with line nodes in UPd 2 Al 3 seems to be confirmed.…”

Section: Introductionmentioning

confidence: 99%

Superconducting gap function in antiferromagnetic heavy-fermion UPd2Al3 probed by angle-resolved magnetothermal transport measurements

et al. 2004

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The superconducting gap structure of heavy fermion UPd2Al3, in which unconventional superconductivity coexists with antiferromagnetic (AF) order with atomic size local moments, was investigated by the thermal conductivity measurements in a magnetic field H rotating in various directions relative to the crystal axes. The thermal conductivity displays distinct two-fold oscillation when H is rotated in the plane orthogonal to the basal ab-plane, while no oscillation was observed when H is rotated within the basal plane. These results provide strong evidence that the gap function ∆(k) has a single line node orthogonal to the c-axis located at the AF Brillouin zone boundary, while ∆(k) is isotropic within the basal plane. This gap structure indicates that the pairing interaction in neighboring planes strongly dominates over the interaction in the same plane. The determined nodal structure is compatible with the resonance peak in the dynamical susceptibility observed in neutron inelastic scattering experiments. Based on these results, we conclude that the superconducting pairing function of UPd2Al3 is most likely to be d-wave with a form ∆(k) = ∆0 cos(kzc).

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Section: Introductionmentioning

confidence: 99%

Superconducting gap function in antiferromagnetic heavy-fermion UPd2Al3 probed by angle-resolved magnetothermal transport measurements

et al. 2004

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“…The reduction of the Knight shift in NMR [12] and the Pauli limiting of H c2 [13] indicate spin singlet pairing in this compound. Nodal superconductivity with horizontal nodes has been suggested from the thermal conductivity data [14] and from the c-axis tunneling data of thin film UPd 2 Al 3 samples [15].…”

Section: Introductionmentioning

confidence: 79%

Gap symmetry of superconductivity in UPd2Al3

et al. 2004

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“…The existence of the line node is suggested by the nuclear magnetic resonance (NMR) measurement [5], in which the Hebel-Slichter peak was absent, and T −1 1 ∝ T 3 was observed. The singlet state is supported by the presence of NMR Knight shift [5], and the Pauli limited upper critical field [6,7]. In recent angle resolved magnetothermal transport measurements [8], two-fold oscillation in the rotation perpendicular to the ab plane was observed, while no oscillation was observed in rotation in the ab plane.…”

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confidence: 91%

“…The singlet state is supported by the presence of NMR Knight shift 5 and the Pauli limited upper critical field. 6,7 In recent angle resolved magnetothermal transport measurements, 8 twofold oscillation in the rotation perpendicular to the ab plane was observed, while no oscillation was observed in rotation in the ab plane. These experimental results are reproduced by the order parameter of the form of ⌬͑k͒ = ⌬ 0 cos͑k z c͒.…”

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Interlayer spin-singlet pairing induced by magnetic interactions in an antiferromagnetic superconductor

Seki

2005

Phys. Rev. B

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It is shown that interlayer spin-singlet Cooper pairing is induced by magnetic interactions in a metallic antiferromagnet of stacked conductive layers in which each layer is ferromagnetically polarized and they order antiferromagnetically in stacking direction. As a result, the antiferromagnetic long-range order and superconductivity coexist at low temperatures. It is shown that T AF Ͼ T c except for in a very limited parameter region unless T AF = 0, where T AF and T c denote the antiferromagnetic and superconducting transition temperatures, respectively. It is found that the exchange field caused by the spontaneous staggered magnetization does not affect superconductivity at all, even if it is very large. The resultant superconducting order parameter has a horizontal line node and is isotropic in spin space in spite of the anisotropy of the background magnetic order. We discuss the possible relevance of the present mechanism to the antiferromagnetic heavy fermion supercon-In this paper, we show that interlayer spin-singlet Cooper pairing is induced by magnetic interactions in a certain kind of metallic antiferromagnet. We consider a layered system of itinerant electrons in which each layer is ferromagnetically polarized but the majority-spin alternates in stacking direction. Therefore the magetic order is characterized by the wave vector Q = ͑0,0, / c͒, where we have assumed the a and b crystal axes to be parallel to the layers, and the c axis in the stacking direction, and c denotes the c axis lattice constant. It is also shown that the exchange field caused by spontaneous staggered magnetization does not influence superconductivity, however large it is.The heavy fermion superconductors, such as UPd 2 Al 3 and CePt 3 Si, can be candidates of the present mechanism. The antiferromagnetic long-range order is considered to be characterized by the wave vector Q = ͑0,0, / c͒, both in UPd 2 Al 3 ͑Ref. 1͒ and in CePt 3 Si. 2 Superconducting transitions have been observed at T c = 2.0 and 0.7 K, below the antiferromagnetic transition temperatures T AF = 14.3 and 2.2 K, in UPd 2 Al 3 ͑Ref. 3͒ and CePt 3 Si, 4 respectively. It has been suggested that the magnetic moment is large, i.e., 0.85 B /U, in UPd 2 Al 3 , 3 but small, i.e., 0.16 B / Ce, in CePt 3 Si. 2 The order parameter of interlayer spin-singlet pairing has a horizontal line node. This also agrees with the experimental results in the compound UPd 2 Al 3 . The existence of the line node is suggested by the nuclear magnetic resonance ͑NMR͒ measurement, 5 in which the Hebel-Slichter peak was absent, and T 1 −1 ϰ T 3 was observed. The singlet state is supported by the presence of NMR Knight shift 5 and the Pauli limited upper critical field. 6,7 In recent angle resolved magnetothermal transport measurements, 8 twofold oscillation in the rotation perpendicular to the ab plane was observed, while no oscillation was observed in rotation in the ab plane. These experimental results are reproduced by the order parameter of the form of ⌬͑k͒ = ⌬ 0 cos͑k z c͒.Coexistence of...

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Temperature and angular dependence of the upper critical field of UPd2Al3 thin films

Cited by 19 publications

References 8 publications

Superconducting gap function in antiferromagnetic heavy-fermion UPd2Al3 probed by angle-resolved magnetothermal transport measurements

Superconducting gap function in antiferromagnetic heavy-fermion UPd2Al3 probed by angle-resolved magnetothermal transport measurements

Gap symmetry of superconductivity in UPd2Al3

Interlayer spin-singlet pairing induced by magnetic interactions in an antiferromagnetic superconductor

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