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The crystallographically ordered Fe x TiSe 2 compounds ( x = 0.25, 0.38, and 0.50) have been investigated as a function of temperature using Mossbauer spectroscopy, susceptibility measurements, and X-ray diffraction. It is found that the coupling between the iron- d localized and the TiSe 2 -band levels decreases as x increases, contrary to what is usually observed for lower iron contents in related disordered materials. For x = 0.50, magnetostriction is evidenced below T N . Besides, the consequences of iron intercalation in TiSe 2 are analyzed from the viewpoint of the crystal dimensionality as deduced from a thermal expansion study.

The susceptibility of the Fe0.25ZrS2 intercalation compound has been shown to depend strongly upon the applied field at lower temperatures. The existence of a cusp at lower fields, together with the fact that the maximum is erased when the sample is field cooled. are attributed to spin-glass properties below 15 K. The 4 K Mossbauer spectrum is magnetic and unresolved, showing a high degree of disorder as far as the spin orientations are concerned. As the temperature is increased, the evolution of the characteristics of the spectra for Fe0.25ZrS2, as well as for Fe0.33ZrS2, are interpreted in terms of a progressive occurrence of fast relaxing spins. Owing to the non-metallic properties of these compounds, the iron-vacancies disordered distribution and the frustration of the exchange interactions are probably at the origin of such a behavior.