The intermetallic compound PrPb3 exhibits antiferroquadrupolar (AFQ) ordering at low temperature. We investigated the magnetic phase diagram through measurements of the specific heat and the magnetocaloric effect. In zero magnetic field the specific heat shows a second-order phase transition with an ordering temperature TAFQ=0.39K in line with earlier results. In addition, we find a further transition at T$∗$=0.35K for 3T and T$∗$=0.49K for 4.5T, which, however, is only observed upon heating. The strong hysteresis between heating and cooling suggests that this transition is of first order. Under hydrostatic pressure of 6.5kbar, the phase diagram is almost unaltered in agreement with an estimate of dTAFQ/dp by Ehrenfest's relation.     «

The intermetallic compound PrPb3 exhibits antiferroquadrupolar (AFQ) ordering at low temperature. We investigated the magnetic phase diagram through measurements of the specific heat and the magnetocaloric effect. In zero magnetic field the specific heat shows a second-order phase transition with an ordering temperature TAFQ=0.39K in line with earlier results. In addition, we find a further transition at T$∗$=0.35K for 3T and T$∗$=0.49K for 4.5T, which, however, is only observed upon heating. Th...     »