Microscopic Description of Rotating Magnetocaloric Effect in Frustrated Antiferromagnetic System TmB4

TmB4 is an anisotropic magnetic system with geometrical frustration of Shastry-Sutherland type. Experimentally, it was the rotating magnetocaloric effect (R-MCE) of TmB4 evaluated from measurements of temperature dependences of heat capacity in various magnetic fields and crystallographic orientations. R-MCE in this system shows a complex behavior of the adiabatic temperature change (AdT) - cooling above T-N and two heating regions in ordered phase [1]. In this contribution, a theoretical model with spin-electron Hamiltonian was suggested to explain the complex AdT behavior. The model is based on the idea of two interacting subsystems: the localized spins of rare earth ions, and the itinerant electrons in conduction band. The received results from Monte Carlo approach successfully reproduce the observed heating and cooling regions. Thus, our study shows that measurements of R-MCE can be an effective tool for investigation of the microscopic properties of magnetization processes.