We present a detailed study of the field (B)- temperature (T) phase diagram under pressures (P) up to 2.7 GPa for the heavy-fermion antiferromagnet YbAgGe that crystallizes in the hexagonal ZrNiAl-type structure with a quasi-kagome lattice of Yb ions. This compound undergoes two magnetic transitions at T M1 = 0.8 K and TM2 = 0.65 K in zero field at ambient pressure. In the ground state, M(B) shows a metamagnetic transition at B M = 4.6 T for the easy magnetization direction B || a. This transition field decreases to 3.3 T as P is increased to 2.2 GPa. At 2.7 GPa, ρ(B) exhibits successive transitions at 5.0, 6.0, 7.5, and 9.0 T. On the other hand, for the hard direction B || c, TM increases with applied field in the P range above 0.5 GPa. This increase of TM(B) is opposite to the decrease of TM(B) for a conventional antiferromagnetic phase. These findings suggest that the application of pressure releases in part the magnetic frustration in YbAgGe.
ASJC Scopus subject areas
- Physics and Astronomy(all)