Giant negative magnetoresistance in quasi-one-dimensional conductor $\mathrm{TPP}\left[\mathrm{Fe}\right(\mathrm{Pc}\left)\right(\mathrm{CN}{)}_2{]}_2:$ Interplay between local moments and one-dimensional conduction electrons

We have found giant negative magnetoresistance in the one-dimensional conductor $\mathrm{TPP}\left[\mathrm{Fe}\right(\mathrm{Pc}\left)\right(\mathrm{CN}{)}_2{]}_2$ below 50 K. The reduction of the resistance is larger in the field perpendicular to the one-dimensional axis than parallel to the axis. The magnetic susceptibility shows anisotropic Curie-Weiss behavior. The experimental results suggest the interaction between the one-dimensional electron system and the local moments. The reduction of the spin scattering of the itinerant electrons by the local moments under the field is proposed as the origin of the giant negative magnetoresistance.