Engineering thermal (in)stability in heteromagnetic nanostructures

forthcoming

Beyond exchange bias systems, where antiferromagnetic layers stabilize ferromagnetic layers, antiferromagnets have seen limited practical use due to their zero net magnetic moment, which hinders both sensing and interaction with the magnetization. However, in comparison with ferromagnets, antiferromagnets intrinsically display orders of magnitude faster magnetization dynamics, making them highly attractive for technological applications. In most nanotechnological applications, flips of the magnetization due to thermal fluctuations are undesirable. For instance, in magnetic storage, thermal switching of the bits compromises data integrity. However, other applications, such as magnetic nanoparticles in biomedicine, crucially rely on it. THERMAGINE fundamentally reimagines the role of antiferromagnets in nanomagnetic heterostructures by exploiting their faster dynamics to speed up thermal switching, contrasting with their use in exchange bias systems. The aims of THERMAGINE are: 1. To achieve a fundamental understanding of the thermal switching dynamics of nanoscale antiferromagnetic and antiferromagnetic/ferromagnetic heterostructures, through an integrated approach that combines state-of-the-art nitrogen-vacancy (NV) microscopy, capable of capturing thermal switching of individual nanostructures, and GPU-accelerated micromagnetic simulations. 2. To apply this knowledge to engineer lithographically defined nanoparticles with faster thermal switching, addressing a key challenge in biomedical applications: creating particles combining large magnetic moments with fast, monodisperse switching - essential for optimal magnetic hyperthermia cancer therapy and complementary magnetic particle imaging (MPI). Beyond unraveling thermal dynamics of antiferromagnets that will be beneficial for the current research on antiferromagnets in spintronics, THERMAGINE will lay the foundation for research toward record-breaking performance in biomedical nanoparticle applications.