Dresden 2009 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 6: Postersession Correlated Electrons: (General) Theory, Low-Dimensional Systems, Kondo Physics, Heavy Fermions, Quantum-Critical Phenomena
TT 6.50: Poster
Montag, 23. März 2009, 13:00–16:45, P1A
Magnetic field dependency of the spin wave excitation gap in UPt2Si2 — •Dirk Schulze Grachtrup1, Matthias Bleckmann1, Stefan Süllow1, and John A. Mydosh2 — 1TU Braunschweig, Institute for Physics of Condensed Matter, Mendelssohnstr. 3, 38106 Braunschweig, Germany — 2University Cologne, II. Physikalisches Institut, Zülpicher Str. 77, 50937 Cologne, Germany
Tetragonal UPt2Si2 has recently been characterized as moderately mass enhanced antiferromagnetic compound, which in various physical properties reveals a resemblance to the hidden order material URu2Si2 [1,2].
To further characterize this resemblance we have examined UPt2Si2 with resistivity measurements in magnetic fields. In particular, we find the antiferromagnetic phase transition at TN=32 K in zero field to shift slightly downwards to 31 K at B = 9 T // c-axis. Further, the temperature dependence of the resistivity in the range up to 20K can be described by an opening of a spin wave excitation gap. In contrast to TN this gap displays a much larger reduction by about 30% with increasing magnetic field up to 9T. We discuss the relationship between spin excitation gap and magnetic ordering, this in particular with respect to the difference in field response.
[1] [t]8.7cmS. Süllow, A. Otop, A. Loose, J. Klenke, O. Prokhnenko, R. Feyerherm, R.W.A. Hendrikx, J.A. Mydosh, H. Amitsuka, J. Phys. Soc. Jpn. 77 (2008) 024708
[t]8.7cmN. Johannsen, S. Süllow, A.V. Sologubenko, T. Lorenz, J.A. Mydosh, Phys. Rev. B 78 (2008) 121103