Magnetoresistance of sintered (Fe2O3)100-x(Fe3O4)x ferrites

Magneto resistance (MR) of the sintered (Fe2O3)(100-x)(Fe3O4)(x) ferrite with x = 15-97 at% were investigated. The M R value was increased from 2.5% for x= 15 to 4.8% for x=97 at room temperature with maximum applied field of 8.8kOe. The plot of log p versus T-1/2 of all sintered samples exhibited a linear relationship, indicating that the dominant MR effect was spin-dependent tunneling between the Fe3O4 phase through alpha-Fe2O3 barrier. The percolation threshold for the conduction paths in this system is in the vicinity of x=40 at%. (C) 2003 Elsevier B.V. All rights reserved.