Local irreversible magnetization rotation of Permalloy thin films on binding papers

In narrow senses, flexible devices consist of soft upholders and functional materials/devices. Such hybrid devices with elastic deformations are promising for broad applications ranging from displays to sensors/detectors and micro/nano mechanical systems (MEMS). In contrast, plastic deformations are typically avoided, because of the common belief that the functionalities of the flexible devices degrade due to irreversible deformations. In this letter, we show that, for exploiting the competition between macro-elastic and local-plastic deformations, on common binding papers, the direction of magnetization in Permalloy thin films realizes a 90 rotation. A positive magnetic anisotropic constant starts at the center of sample, approaches zero after leaving from the center, and then increases its strength gradually with a negative sign until the sample edge, following an approximately linear relationship. In addition, the magnetic stability of the samples improved owing to the residual stress of the local-plastic deformations, as well as diversification of functionality and transfer are easy to be implemented by the composite substrate.