¹ Department of Physics, Sri Krishnadevaraya University, Anantapuramu 515003, India;

² Department of Physics, Government College (A), Ananthapur 515001, India;

³ Department of Physics, Chaitanya Bharathi Institute of Technology, Hyderabad 500075, India;

⁴ Department of Information Systems, College of Computer and Information Sciences, Majmaah University, Al'Majmaah 11952, Saudi Arabia

* Correspondence: Siva Sankara Reddy, reddy.lss@gmail.com; D. Baba Basha, b.dudekula@mu.edu.sa

Bi_1−xNi_xFeO₃ (x = 0.20–0.80) nanoparticles were prepared using the hydrothermal method. Rhombohedral structure along with few secondary phases are confirmed from obtained X-ray diffraction (XRD) patterns. The microstructure confirmed structures similar to nanospheres and small nanorods. An agglomeration is noticed among the nanoparticles of x = 0.2–0.8 owing to magnetic interactions. The Tauc’s plots are drawn to evaluate the optical bandgap (E_g) as a function of Ni-content. The dielectric constant, and loss parameters were studied as a function of Ni-content and frequency. In addition, the dielectric modulus formalism was discussed to evaluate the space charge effect and charge carrier behavior. The Nyquist plots were drawn and noted to be incomplete relaxation for all the samples.