Thermodynamic properties of a superconductor interfaced with an altermagnet

Recently introduced magnetic materials called altermagnets (AM) feature zero net magnetization but a momentum-dependent magnetic exchange field, which can have intriguing implications when combined with superconductivity. In our work, we use the quasiclassical framework to study the effects of such a material on a conventional superconductor (S) in an AM/S bilayer. We discuss the superconducting phase diagram and heat capacity of AM/S while making a comparison with a ferromagnet-superconductor bilayer. Furthermore, we examine the density of states and analyze the system's response to an external magnetic field. We illustrate the anisotropy of spin susceptibility and magnetization of AM/S by considering an external field in the in-plane and out-of-plane directions, thereby facilitating the scope of experimental detection and characterization of an AM in an AM/S hybrid system. Published by the American Physical Society 2025