Magnetic Phase Diagram of $TmB_{4}$ under High Pressure

$TmB_{4}$ is a Shastry-Sutherland frustrated system which exhibits very complex magnetic properties. In this contribution the phase diagram of magnetic field vs. temperature of $TmB_{4}$ under hydrostatic pressure up to 26.5 kbar is investigated using sensitive ac-resistance measurements. Temperature and magnetic field dependences of resistance at various pressures were carried out in a piston cylinder pressure cell between 1.7 and 14 K and in magnetic fields up to 6 T. The obtained results exhibit shifts of ordering temperatures $T_{N}$ as well as shifts of boundaries between different magnetic phases. The observed pressure dependences of $T_{N}$ can be described by the relation d $lnT_{N}$/dp=+(0.16÷0.18) %/kbar. The effect of pressure on various interactions between magnetic ions in this compound is discussed.