Abstract
We present a superconducting phase diagram of UPt3 for a field at 45° to the c-axis constructed from high-resolution ultrasonic velocity measurements. It is unambiguously determined that the HFL(T) line intersects the Hc2(T) line where a kink is observed. The available data favors the interpretation that the H(Tc*) line terminates on the HFL(T) line at a different point.
Original language | English (US) |
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Pages (from-to) | 170-172 |
Number of pages | 3 |
Journal | Physica B: Physics of Condensed Matter |
Volume | 199-200 |
Issue number | C |
DOIs | |
State | Published - Apr 2 1994 |
Funding
The resultant superconducting phase diagram of UPt3 for the field at 45 ° to the c-axis is shown in Fig. 4. As the HFL(T) and H¢z(T) transitions are distinguishable even within the width of the merging transitions, one traces the HFL(T) transition line to intersect with the Hcz(T) line (at point H in Fig. 4), where a kink on the H,~(7) curve is observed. On the other hand, the Hc,(T) line seems to intersect the HvL(T) line at a point slightly away from the previous critical point. This suggests two tri-critical points instead of a single tetracritieal point in the HT plane for this field orientation. However, the possibility for the existence of a single tetraeritieal point is not ruled out yet, due to the relatively small steps and broad width of the H(Tc,) transitions. Nevertheless, this new phase diagram confirms that for fields along a nonsymmetric axis of the crystal, the phase boundaries line do not repel each other to give two non-intersecting continuous phase boundary lines. In conclusion, the topology of this new phase diagram with the field at 45' to the c-axis resembles to a large extent those with fields along and perpendicular to the c-axis, it is unambiguously determined that the Hvt(T) line intersects the Hcz line where a kink is observed. The available data favors the interpretation that the H(T~,) line terminates on the HFL(T) line at a different point. The research was supported by the Office of Naval Research (UWMI; by NSF under grants DMR-90-11562 and DMR-9121654 (Cornell)and DMR-89-07396 DMR 912052 i (Northwestern).
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Electrical and Electronic Engineering