Preparation and Physical Properties of Stretchable FeRh Films with Periodic Wrinkle Structure

Stretchable magnetic materials are highly desirable for developing flexible high‐performance magnetoelectronic devices. However, it is still challenge to fabricate stretchable magnetic films with high growth temperature. In this work, metamagnetic FeRh films are grown on mica substrates at high temperature and then transferred onto the prestrained polydimethylsiloxane (PDMS). Due to the large modulus mismatch between FeRh films and PDMS, FeRh films with periodic wrinkle pattern is formed after releasing the prestrain, enabling a controllable stretchability up to a few tens of percent. Moreover, the meta‐magnetic phase transition temperature can be effectively controlled by the prestrain, with an increase of ≈4 K for every 10% increase in the prestrain. In case of the applied tensile strain less than the prestrain, the obtained flexible FeRh films can maintain stable performance after thousands of stretches, making it promising for applications in flexible magnetoelectronic devices. In this work, a method is developed for preparing stretchable metamagnetic FeRh films, which exhibit controllable and strain‐insensitive magnetic properties. This method is especially suitable for films which need a high growing temperature. The obtained flexible FeRh films with periodical wrinkle structure can be stretched up to a few tens of percent with their properties remaining stable.