Münster 1997 – scientific programme
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TT: Tiefe Temperaturen
TT 6: Postersitzung I: Mesoskopie(1-21), amorphe Metalle und Defektsysteme(22-29), Kryotechnik, Kernmagnetismus(30-37), festes N2(38), Quantenflüssigkeiten und -kristalle(39-48), dünne supraleitende Filme(49-68), schwere Fermionen und Kondosysteme(69-92), Fullerene(93-94)
TT 6.85: Poster
Tuesday, March 18, 1997, 09:30–13:00, Z1
Breakjunction Tunneling Study of the Heavy-Fermion System CeB6 — •A. Nowack1, R. Keijsers2, S. Wasser1, and H. van Kempen2 — 1II. Phys. Institut Universität Köln, Zülpicher Str. 77, 50937 Köln — 2Research Institute for Materials, University of Nijmegen, Toernoiveld 1, 6525 ED Nijmegen, The Netherlands
We prepared low-area metallic point-contacts and vacuum tunnel junctions from single-crystals of the heavy-fermion system CeB6 using the break-junction technique [1] and studied their dV/dI(V)-characteristics at liquid-helium temperatures. The characteristics of small (down to atomic-size) point-contacts and tunnel junctions show a narrow zero-bias resistance maximum (width ≈ 10meV) with a logarithmic voltage dependence of the differential resistance. We believe that this structure is connected with the Kondo-resonance in CeB6. The observation of a resistance maximum is comparable to results obtained on thin-film tunnel junctions on Kondo alloys [2], but opposite to the case of tunneling through a barrier with magnetic impurities. In contrast to break-junction results for Kondo alloys, we do not observe a significant dependence of the width of the zero-bias peak on the contact size [3].
[1] C.J. Muller et al., Physica C 191, 837 (1992)
[2] S. Bermon et al., Phys. Rev. Lett. 40, 53 (1978)
[3] I.K. Yanson et al., Low Temp. Phys. 20, 836 (1994)