Non-saturating, Sub-Liner Magnetoresistance in bulk Ge₂Sb₂Te₅

Phase Change materials (PCM) rapidly and reversibly switch or transform between amorphous and crystalline states. This microscopic repositioning of the system in the lattice level may give rise to large macroscopic differences in physical properties; these changes in technologically important electrical, thermal and optical parameters were discovered in 1960’s. Ambient temperature operable PCM’s are utilized in electronic flash memory drives and in optical data storage devices. Previously we have reported on a well-known PCM alloy Ge₂Sb₂Te₅; where, based on Noritheim-Gorter like scaling between Seebeck coefficient (S) and electrical conductivity (s) we have argued the existence of two distinct types of scattering. Here we report the high magnetic field magnetoresistance in poly-crystalline specimens Ge₂Sb₂Te_5, especially in the low temperature regime. We observe a relatively strong increase in the ohmic resistance in response to the applied magnetic field, about 150% increase between 0 - 18 T. The transport data can be precisely described by empirical functions, however, the behavior does not follow the well-known Kholer’s rule. Overall, the field dependence is sub-linear but does not quite saturates up to 18 T even in the sub-kelvin range.