Measurement of pressure effects on the magnetic and the magnetocaloric properties of the intermetallic compounds DyCo2and Er(Co1−xSix)2

The effect of external pressure on the magnetic properties and magnetocaloric effect of polycrystalline compounds DyCo 2 and Er(Co 1− x Si x ) 2 ( x = 0,0.025 and 0.05) has been studied. The ordering temperatures of both the parent and the Si-substituted compounds are found to decrease with pressure. In all the compounds, the critical field for metamagnetic transition increases with pressure. It is seen that the magnetocaloric effect in the parent compounds is almost insensitive to pressure, while there is considerable enhancement in the case of Si-substituted compounds. Spin fluctuations arising from the magnetovolume effect play a crucial role in determining the pressure dependence of the magnetocaloric effect in these compounds. The variation of the magnetocaloric effect is explained on the basis of the Landau theory of magnetic phase transitions.