Effect of volume fractional change of nanoparticles on surface plasmon polariton Zahid Ullah, Muhammad Usman, Prakash Kanjariya, Asha Rajiv, Aman Shankhyan, Sachin Jaidka and A. S. Madhusadan Acharyulu EPL, 149 5 (2025) 55001 Published online: 10 March 2025 DOI: 10.1209/0295-5075/ada969