Anomalous magnetocaloric effect in YbAs associated with the giant quadrupolar interaction

We report a theoretical investigation that predicts the existence of anomalous magnetocaloric effect in the YbAs compound. The YbAs coot upon magnetizing and warm upon demagnetizing, in the temperature range between 33 and 84 It for external magnetic field change from 0 to 23.5 T. The anomalous effect can be observed on the negative part of magnetic entropy changes, upon variation of the external magnetic field, in an isothermic process. This study was carried out using a model Hamiltonian, which takes into account the crystalline electrical field and the quadrupolar interactions within the molecular-field approximation.