Changes in recording tape magnetization produced by stress

When mechanical forces are applied to single domain particles that are used in magnetic recording tapes, the resultant stress anisotropy energy alters the magnetized state, producing reversible and irreversible changes. We use four different experimental techniques to measure these changes and analyze the results in terms of the values for the saturation magnetostriction constants (λ s ) and the applied stress (σ x ). The reversible changes in magnetization (M x ) are roughly proportional to \lambda_{s}\sigma_{x} ; the greatest irreversible or loss component occurs when the product of σ x and λ s along the magnetizing axis ( x ) is negative, increasing when major easy axes make large angles with x .