Measurement of saturation magnetostriction using novel strained substrate techniques and the control of the magnetic anisotropy

A simple new technique is described for the measurement of saturation magne tostriction in thin films deposited onto rigid substrates. The method is ba sed on mechanically introducing a small curvature in the substrate either d uring the deposition (strained growth) or post-deposition. The :strain-indu ced anisotropy is measured using the magneto-optical Kerr effect. Quantific ation of the film strain is obtained using optical interference and stylus measurements; coupled with mechanical finite-element modelling, this allows the saturation magnetostriction to be determined. No information about the mechanical properties of the substrate is required, and providing that the Young's modulus of the film is known accurately, the values of magnetostri ction obtained are accurate and absolute. It is envisaged that the techniqu e could be applied to a wide variety of films deposited onto commerciality important substrates. Here, it is applied to amorphous films based on the M ETGLAS(R) 2605SC composition deposited onto glass and silicon substrates. A high degree of control is also demonstrated in tailoring the anisotropy fi eld, by the technique of substrate straining. (C) 1999 Elsevier Science B.V . All rights reserved.