PACS 75.70.CnIrMn-pinned top spin valve (TSV) and bottom spin valve (BSV) films were prepared by DC magnetron sputtering onto thermally oxidized Si (111) substrates at room temperature under a magnetic field of above 100 Oe. The effect of cyclic annealing treatments on magnetoresistive and structural properties in the films was investigated. The exchange coupling field (H ex ) of TSV and BSV is stabilized after the second annealing cycle and it is thought that these films reveal high thermal stability. The magnetoresistance (MR) ratio and H ex of TSV were 5.6% and 430 Oe, respectively. For BSV the H ex value (1180 Oe) is much higher while MR ratio (3.6%) is reduced with respect to TSV. The blocking temperatures of the TSV and BSV were 250 °C and 270 °C, respectively. The results concerning magnetic properties together with structural investigations suggest the H ex is mainly dependent on the quality of fcc (111) crystalline texture while MR is sensitive to both crystalline texture and interface roughness.