Electromagnetic Interference Shielding Effect on the Strongly Correlated electron System NiWO4 Embedded in PDMS

The insulators in strongly correlated electron systems (SCES) exhibit exotic condensed matter phenomena due to the inherent strong Coulombic repulsion between magnetic cations within their crystal structures, which leads to polaronic hopping conduction, characterized by a high activation energy for carrier transport, and results in unique magnetic properties that vary with environmental conditions. Consequently, the physical properties of SCES insulators can be modulated by tailoring Coulombic repulsion through substitutional doping. In this study, we explore the electromagnetic interference (EMI) functionality of NiWO₄ SCES, which is tuned by substituting magnetic cations (X = V, Co, and Fe) at the Ni site. The magnetic cation-doped NiWO₄ SCES powders were synthesized via solid-state methods and confirmed as single-phase materials through X-ray diffraction (XRD) analysis. To fabricate the EMI film, NiWO₄ powders were mixed with polydimethylsiloxane (PDMS), followed by spin-coating and vacuum oven drying. Although the NiWO₄-PDMS composites were physically mixed, as confirmed by optical measurements such as FT-IR and photoluminescence, the composite exhibited a reflection loss of approximately − 3 dB within the frequency range of 25–40 GHz. Upon substitution of magnetic cations at the Ni site, the X-NiWO₄ samples demonstrated an enhanced reflection loss of -8 dB, attributed to variations in magnetization. These findings highlight the EMI functionality of NiWO₄ SCES and the potential for further enhancement through magnetic cation doping. Given the simple composition of the NiWO₄-PDMS system, SCES materials introduce the potential for advanced EMI functionality, providing insights into different mechanisms that can be achieved through optimized structural and compositional modifications.