Ground state and stability of the fractional plateau phase in metallic Shastry-Sutherland system TmB4

We present a study of the ground state and stability of the fractional plateau phase (FPP) with M/M-sat=1/8 in the metallic Shastry-Sutherland system TmB4. Magnetization (M) measurements show that the FPP states are thermodynamically stable when the sample is cooled in constant magnetic field from the paramagnetic phase to the ordered one at 2 K. On the other hand, after zero-field cooling and subsequent magnetization these states appear to be of dynamic origin. In this case the FPP states are closely associated with the half plateau phase (HPP, M/M-sat=1/2), mediate the HPP to the low-field antiferromagnetic (AF) phase and depend on the thermodynamic history. Thus, in the same place of the phase diagram both, the stable and the metastable (dynamic) fractional plateau (FP) states, can be observed, depending on the way they are reached. In case of metastable FP states thermodynamic paths are identified that lead to very flat fractional plateaus in the FPP. Moreover, with a further decrease of magnetic field also the low-field AF phase becomes influenced and exhibits a plateau of the order of 1/1000 M-sat.

Automated summary

The study investigates the ground state and stability of the fractional plateau phase (FPP) with M/M-sat=1/8 in the metallic Shastry-Sutherland system TmB4. It shows that FPP states are thermodynamically stable during cooling from the paramagnetic phase to the ordered one at 2 K, with a dynamic origin observed after zero-field cooling. The FPP states are closely linked to the half plateau phase (HPP) and influence the low-field antiferromagnetic (AF) phase, with stable and metastable FP states observed depending on the thermodynamic paths taken.