Relationship between film structure and exchange coupling in Mn-Ir/Ni-Fe films

Exchange couplings between Mn-Ir antiferromagnetic layers and Ni-Fe magnetic layers have been investigated in Hf(8 nm)/Mn-Ir(16 nm)/Ni-Fe (5 nm)/Hf(7 nm)/Si(1 0 0) films formed by ion-beam sputtering. When the acceleration voltage of the ion gun was higher than 600 V and the ion current was 50-100 mA, the FCC-(1 1 1) texture of the Mn-Ir layer became strong and the Mn-Ir crystallites were relatively large. The large crystallites caused strong exchange couplings between the Mn-Ir layers and the Ni-Fe layers. The highest exchange bias field was 14.8 kA/m. A Ta (7 nm)/Mn-Ir(14 nm)/Ni-Fe (5 nm)/Ta (6 nm)/Si(1 0 0) him was also prepared by RF sputtering. The RF -sputtered film had the larger crystallites than the ion-beam-sputtered :films, The exchange bias field was 23.1 kA/m.