Magnetostriction in spin valves

We report an accurate method for the measurement of the saturation magnetos triction lambda(s) of thin conducting ferromagnetic films using spin valve structures. We describe an alternative to the cantilever beam method, calle d the bending method, which utilizes the inverse magnetostrictive effect. T ypical soft ferromagnetic films exhibit hysteretic magnetization loops, whi ch make the measurements of the magnetoelastic energy (hence lambda(s)) imp recise or erroneous. We show how to resolve the hysteresis problem by appli cation of a transverse field. We also demonstrate the quantitative connecti on between the cantilever and bending method in a comparative study of film s spanning a large magnetostriction range. The sensitivity of measurement o f magnetostriction using the bending method is better than 1 x 10(-7). (C) 1999 American Institute of Physics. [S0021-8979(99)79508-3].