Magnetocaloric and thermal properties of Ho(Co1-xSi x)2 compounds

Abstract

The specific heat and thermal conductivity of HoCo2 and Ho(Co0.95Si0.05)2 were measured as functions of temperature in several constant magnetic fields up to 8 T. From a specific-heat data analysis the isothermal entropy change and the magnetocaloric effect (MCE) have been evaluated in a wide temperature range for several values of the applied magnetic field. The considerable values of the magnetocaloric effect in the vicinity of the magnetic ordering transition are qualifying both compounds as suitable for magnetic refrigeration purposes. The magnetic phase transition temperature (7C) increases from 77 K for HoCo2 to 103 K for Ho(Co0.95Si0.05)2 while the large MCE in the vicinity of TC is maintained, which demonstrates ways of tuning the operating temperatures of the magnetic refrigerant. © 2007 Verlag der Zeitschrift für Naturforschung,.