Tailoring magnetic anisotropy of permalloy thin film by functionalizing PDMS substrates

Abstract Ar-Plasma treatment is an effective and scalable technique for tailoring surface properties of polydimethylsiloxane (PDMS), enabling precise control over the morphological and mechanical properties of the surface layer. Varying plasma power modulates the PDMS surface, increasing hydrophilicity and stiffness by forming a silica-like layer. In this work, we demonstrate that these changes significantly influence the magnetic properties of a subsequently deposited thin permalloy (Py) film, notably suppressing uniaxial anisotropy in a power-dependent manner. To quantify these effects, we extract the hysteresis loop squareness, defined as the ratio of Mₑ/Mₒ M r / M S, as a function of angle. Suppressing anisotropy with plasma power demonstrates the capability to tune magnetic properties via substrate modification. These results open new opportunities for designing flexible magnetic systems for the next generation of electronics and flexible spintronics devices. Graphical abstract