Semnan University Press Progress in Physics of Applied Materials 2783-4794 5 2 2025 11 01 Exploring Bismuth-Induced Structural Modifications and Magnetic Phase Transitions in CuFe2O4 Ferrite 107 117 9641 10.22075/ppam.2025.35536.1120 EN Hamid Hamrah School of Physics, Damghan University, Damghan, Iran Ahmad Gholizadeh School of Physics, Damghan University, Damghan, Iran Journal Article 2024 11 07 The effects of diamagnetic bismuth substitution on the microstructural and magnetic properties of sol-gel auto-combustion citrate nitrate synthesized CuFe<sub>2-x</sub>Bi<sub>x</sub>O<sub>4</sub> (x=0.0, 0.4, 0.8, 1.2, 1.6 and 2.0) nano powders were investigated. The samples were characterized by techniques such as X-ray diffraction, Raman spectroscopy, Fourier-transform infrared spectroscopy, field-emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, UV-Vis diffuse reflectance spectroscopy, and vibration sample magnetometer. The structural results showed a phase transition from a predominantly tetragonal structure with an I4<sub>1</sub>/amd space group to a tetragonal structure with a P ncc space group. The magnetic properties of the samples revealed a transition from a ferrimagnetic to a diamagnetic phase due to the presence of the diamagnetic Bi<sup>3+</sup>. Although the coercive field exhibited a minimum value at a substitution level of x = 0.8, the saturation magnetization was found to decrease with increasing Bi substitution, ranging from 25.04 emu/g for x = 0.0 to -0.02 emu/g for x = 2.0. Copper spinel ferrite Copper Spinel Bismuth Citrate Method Structural Phase Transition Ferrimagnetic to Diamagnetic Transition https://ppam.semnan.ac.ir/article_9641_8b7bf8f76014b62ea84c7a56de8c26c2.pdf