Magnetic anisotropy and crystal structure distortions in ErB4

We propose to investigate the unusual low-temperature behaviour of single crystal ErB4 in an applied magnetic field. At room temperature, the compound has a tetragonal structure in which the magnetic Er ions form a network of squares and triangles in that maps to the Shastry-Sutherland lattice, a rare example of highly frustrated system with an exact ground state solution. It has recently been found through the magnetisation and magnetostriction measurements that a significant anisotropy of magnetic properties develops in the nominal a-b plane at low temperature due to the crystal structure distortions. We propose to probe the field-induced magnetic arrangements for the field applied along ‘a’ and ‘b’ axes, particularly for higher fields where a magnetisation plateau of totally unknown origin is found. WISH with its high-field magnetic is ideally positioned for the task in hand.