Negative magnetoresistance in crystals of the paramagnetic intercalation compound MnxTiS2

Transverse magnetoresistance for paramagnetic MnxTiS2 (0.02 less than or equal to x less than or equal to 0.25) crystals has been measured at three fixed temperatures 77, 4.2, and 1.8 K at fields up to 31 T using a compact home-made pulsed magnet. We have found a large negative magnetoresistance Delta rho/rho(0) at low temperatures. For example, Delta rho/rho(0) for x=0.25 is of the order of 40% at 1.8 K and 31 T and shows a cubic dependence on the magnetization M, Delta rho/rho(0) alpha -(M/M-s)(3) (M-s: saturation magnetization), rather than a quadratic dependence Delta rho/rho(0) proportional to-(M/M-s)(2) which is found for many ferromagnetic materials. Qualitative discussions for the negative magnetoresistance in the layered structure of Mn(x)Tis(2) are given by considering a transport process through host TiS2 ''intralayers'' and its ''interlayers'' via intercalated Mn atoms in the van der Waals gaps. The magnetic field dependence of the negative magnetoresistance can be reasonably explained by the existing spin-fluctuation theory. [S0163-1829(97)01741-4].