Fabrication and magnetoelectronic properties of field aligned CrO 2 powders

Abstract

We have combined field alignment technique together with lithography to fabricate CrO2 powder based devices. A systematic study of the temperature-dependent magnetoelectronic properties has been carried out. The devices exhibit strong anisotropy along the alignment direction at all temperatures. Temperature dependent analysis of the hysteresis loops shows that coercivity of the field aligned powders increases with decreasing temperature. The conduction mechanism has been examined in detail and a transition from tunneling across grain boundaries to inelastic hopping was observed at 215 K. This transition temperature shifts to 230 K in the presence of 10 kOe field cooling due to reduction of the spin-independent hopping conductance channel. © 2006 WILEY-VCH Verlag GmbH & Co. KGaA.