Chapter 9: "Ac susceptibility studies on magnetic materials"

In the present chapter a concise review concerning the AC susceptibility technique applied to bulk magnetic compounds, and thin films is presented. The measurement of the dynamical properties of magnetic compounds has become extremely important in the understanding of complex magnetic phenomena such as spin glass and spin glass like transitions; moreover the employment of very low magnetic fields allows to better analyze these phenomena with no consistent modifications of the original magnetic structure. After a brief introduction in the first paragraph outlining the importance of the AC susceptibility in the analysis of the magnetic behavior of complex compounds, a few details about the theory and the measurement apparatus are reported respectively in sections 2 and 3. In section 4 a selection of representative linear and non linear AC susceptibility measurements are reported performed either as a function of temperature either as a function of a bias applied DC field.