Multifunctional Spin-Dependent Tunneling: From Tunnel Magnetodielectric to Magneto-Optic and Faraday Effects

Magnetic granular nanocomposites, consisting of magnetic nanogranules dispersed within a host matrix, represent a versatile class of functional materials that enable control over electrical, magnetic, and thermal properties at the nanoscale. Over the past decade, by leveraging electrons as carriers of spin, charge, and heat, these features have enabled the discovery of a family of tunnel related phenomena: tunnel magnetoresistance (TMR), tunnel magneto-Seebeck (TMS), tunnel magnetodielectric (TMD), and most recently tunnel magneto-optical (TMO) effects. Their structural features allow for tuning of granular size, distribution, and intergranular spacing, positioning these materials as promising candidates for miniaturized magnetic field sensors, antennas, microwave devices, and spintronic components.