PROPERTIES OF ISING MAGNETIC SYSTEM FexTiS2

Analysis of frequency dependence of spin glass transition temperatures of an Ising spin glass Feo.lTiS2 shows that power law with a finite transition temperature is the most probable formula describing the experimental data. Magnetization measurement on FellaTiS2 suggests that atomically ordered FellsTiSz is an antiferrornagnet with TN = 33 K . Various transition metals are intercalated in the van der Waals gap between the neighboring sulfur layers of hexagonal TiSz. Iron atoms in Fe,TiSz are distributed in ordered manners for x = 1/4, 1/3 and 1/2, forming ordered magnetic compounds; they are randomly distributed for other values of x, forming random magnetic compounds. The magnetic properties of random compound Fe,TiSz have been studied by several authors [I]. The compound with 0 < x 5 0.35 is an Ising spin glass and that with 0.35 < a: 5 0.43 is an Ising ferromagnet. Transition to spin glass state is suggested at low temperature for 0.35 < a: < 0.4. On the other hand, few studies have been made about the magnetic properties of ordered compounds [2]. Here we report two new results: result of ac-susceptibility measurements in the spin glass phase x = 0.1, and magnetic property of ordered compound x = 1/3. There are many exampl'es about the frequency (f) dependence of the paramagnetic-to-spin-glass transition temperature Tg (f) of a spin glass defined by the cusp in ac-susceptibility x,. Several functions are proposed to explain the frequency dependence of T,. The Fulcher law f = foexp [-Eo/k (T, To)] (1) was phenomenologically proposed 131, although its significance is not clear. Short-range Ising model [4] lead to a power law with a zero-temperature transition,