Vortex core transition in superfluid 3He-B

The phase transition between two quantized vortices was mapped in the pT-plane using magnetization and susceptibility anisotropy of the core structures [PRL 53, 584 (1984)]. Strong metastability over the re-entrantly shaped transition line was observed indicating first-order nature of the phase transition.

FIGURE Observed transitions on the phase diagram of rotating He3-B: open circles, H = 284 G (NMR experiment); closed circles, H = 0; crosses, H = 40 G (gyroscope  experiment). There is a slight difference between in the vortex core transition (open circles) and the superflow transition (closed circles and crosses); near Tc, the influence of the magnetic field on the vortex core structures becomes important, which may explain the difference in the transition curves when approaching the Tc curve.


The first-order phase transition in the core structure of quantized vortices, first observed using NMR methods, was investigated in this work in more detail using both the NMR and gyroscopic techniques. Re-entrant shape of the transition curve on the pT plane was observed in both experimental investigations. The gyropscopic experiments revealed that, besides discontinuous magnetic properties, the two vortex types display clearly different critical flow velocities.

At the time of this work, only the vortex present in regions I and III could be identified. According to Ginzburg-Landau theory, this vortex  has a core occupied by A-phase liquid, which is responsible for the susceptibility anisotropy and by ferromagnetic β\beta-phase liquid, with spontaneous magnetization.
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