The bounds of saturation magnetostriction in polycrystalline materials

The universally used approximation for the magnetostriction constant of a polycrystalline material is based on the assumption of uniform stress through the aggregate. In this article we calculate the alternative approximation of uniform strain. The calculation is performed in terms of the grains orientation distribution (texture) function, and single crystal constants describing the elastic and magnetostrictive anisotropy. These bounds represent the optimum solution of the incompletely specified problem of crystallites shape distribution in a polycrystalline aggregate. The available experimental data are compared with the two approximations. (C) 1997 American Institute of Physics.