Mikhail Ryazanov

LARGE MAGNETORESISTANCE EFFECTS IN NOVEL LAYERED RARE EARTH HALIDES

We give a survey of the structures, electric, magnetic and magnetoresistance prop- erties of the two novel low dimensional rare-earth halide systems, GdI2 and GdIHy (2/3 < y ≤ 1). The large magnetoresistance effect observed for GdI2 can be understood on the basis of a conventional spin disorder scattering mechanism, however, strongly magnified by the structural anisotropy and the special topology of the Fermi surface. Bound magnetic polarons are formed in GdIHy leading to a metal insulator transition below ≈ 30 K. The mobility of the magnetic polarons can be effectively modified by external magnetic fields resulting in the large experimentally found magnetoresistance.