DEMAGNETIZATION BY STRESS IN IRON-OXIDE FILMS WITH LARGE PERPENDICULAR MAGNETIC-ANISOTROPY

The origin of the large perpendicular magnetic anisotropy energy of Fe//3O//4 films with (111) orientation has been investigated. The film deposited at substrate temperature Ts about 270 degree C, where (111) oriented films are obtained, has a large positive magnetostriction constant lambda s of about 65 multiplied by 10** minus **6 and receives a large compressive stress of about 1 multiplied by 10**1**0 dyn/cm**2 from the substrate. Besides, the stress applied normal to the film plane leads to a remarkable decrease in the remanent magnetization of the film. These results indicate that the perpendicular magnetic anisotropy latent in the film is caused by the stress induced anisotropy. Read/Write characteristics of the Fe//3O//4 thin film disk measured with a ring head show that perpendicular magnetic recording is realized in the film, though the reproduced output voltage decreases significantly with the repetition of the reproducing process.