LOW-FIELD MAGNETIZATION AND AC MAGNETIC-SUSCEPTIBILITY OF SPIN-GLASSES AND CLUSTER-GLASSES OF ITINERANT MAGNET FEXTIS2

Magnetizations and ac magnetic susceptibilities at low magnetic fields using a SQUID magnetometer have been measured for spin-glass (SG; x = 0.1 and 0.2) and cluster-glass (CG; x = 1/4 and 1/3) phases of FexTiS2 over the frequency range 0.5-100 Hz and temperature range 4.2-80 K. The frequency and temperature variations of the ac magnetic susceptibilities have different behaviors for SG and CG; in particular, the estimated distribution function of relaxation time g(omega, T) for x = 1/4 has a double-peaked shape. The dimensionality and criticality of the CG phases are also discussed. Monte Calro simulations using a site-percolation model with a two-dimensional triangular lattice are made by taking into account the 1st, 2nd, and 3rd nearest neighbors to obtain the percolation probability P.