Thermal modulation studies of the critical magnetic susceptibility of Gd

The technique of temperature modulation of the AC magnetic susceptibility is used for the first time to examine the critical region above a ferromagnetic-paramagnetic transition. The temperature modulation and low-field susceptibility data indicate a well defined critical exponent behaviour chi = chi 0 epsilon - gamma , where epsilon =(T-T c )/T c for polycrystalline Gd, and lead to the critical parameters gamma =1.24+or-0.03 and chi 0 =0.001 for 9.9*10 -3