Regensburg 2013 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 53: Correlated Electrons: Heavy Fermions
TT 53.2: Vortrag
Donnerstag, 14. März 2013, 09:45–10:00, H19
High field Hall measurements on UPt2Si2 at very low temperatures — •Dirk Schulze Grachtrup1, Ilya Sheikin2, Stefan Süllow1, and John A. Mydosh3 — 1Institut für Physik der Kondensierten Materie, Braunschweig, Germany — 2Grenoble High Magnetic Field Laboratory, Grenoble, France — 3Kammerlingh Onnes Laboratory, Leiden, The Netherlands
Tetragonal UPt2Si2 is a moderately mass enhanced antiferromagnet with a transition temperature TN = 32 K in zero magnetic field. Moreover, in magnetization and resistivity measurements in high magnetic fields multiple features indicating new field induced phases have been observed. These features, together with signs of Fermi surface effects point to a significant role of the Fermi surface in UPt2Si2 [1].
Here, we present new magnetoresistivity and Hall effect data on UPt2Si2 at temperatures 50 mK to 2 K in magnetic fields up to 34 T. For the a axis this field range only covers the AFM phase. Instead, for the c axis, we observe a broad maximum in the magnetoresistivity in the field range ∼ 25 to ∼ 33 T indicating the transition into one of the high field phases. Additionally, the magnetoresistivity is hysteretic at all temperatures, with multiple steps appearing at temperatures below ∼ 530 mK. Moreover, in the Hall signal we observe a significant change with an increase of the Hall coefficient by about 40% in the field range 23 - 26 T, this independent of temperature. These findings are discussed in the context of the proposed magnetic phase diagrams and the possibility of the occurence of a Lifshitz transition.
[1] D. Schulze Grachtrup et al., Phys. Rev. B 85, 054410 (2012)