Fractional magnetization plateaus and magnetic order in the Shastry Sutherland magnet TmB4

TL;DR

This paper explores the complex magnetic phases of TmB4, revealing fractional magnetization plateaus and stripe orders, and proposes a connection to fractional quantum Hall physics through an effective model.

Contribution

It introduces a detailed phase diagram of TmB4, identifying fractional magnetization plateaus and linking magnetic behavior to quantum Hall phenomena via an effective S=1/2 model.

Findings

Identification of fractional magnetization plateaus at 1/7, 1/8, 1/9

Observation of stripe magnetic structures

Proposal of a connection to fractional quantum Hall effect

Abstract

We investigate the phase diagram of TmB4, an Ising magnet on a frustrated Shastry-Sutherland lattice by neutron diffraction and magnetization experiments. At low temperature we find Neel order at low field, ferrimagnetic order at high field and an intermediate phase with magnetization plateaus at fractional values M/Msat = 1/7, 1/8, 1/9 ... and spatial stripe structures. Using an effective S = 1/2 model and its equivalent two-dimensional (2D) fermion gas we suggest that the magnetic properties of TmB4 are related to the fractional quantum Hall effect of a 2D electron gas.