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

We present a study of the ground state and stability of the fractional plateau phase (FPP) with M/M = 1/8 in the metallic Shastry-Sutherland system TmB. 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.

Rotating magnetocaloric effect and unusual magnetic features in metallic strongly anisotropic geometrically frustrated TmB.

We have investigated the rotating magnetocaloric effect (R-MCE) of TmB - an anisotropic magnetic system with geometrical frustration of Shastry-Sutherland type. The R-MCE was obtained from detailed temperature dependencies of heat capacity in various magnetic fields of a single crystalline sample for crystal axes orientations c || B and c ⊥ B. The received results exhibit rather complex distributions of positive and negative entropy ΔS(T, B) and temperature ΔT(T, B) differences below and above T when the direction of the magnetic field changes between directions c || B and c ⊥ B.