ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Effect of Mo substitution on structure, morphology and magnetic features of Sr_0.8Ni_0.2Fe_12−2xMo_xO₁₉ (x ≤ 0.35) hexaferrites

M. A. Almessiere, S. Güner, Y. Slimani, A. Demir Korkmaz, and A. Baykal

Department of Biophysics, Institute for Research and Medical Consultations (IRMC), Imam Abdulrahman Bin Faisal University, Dammam, Saudi Arabia

E-mail: malmessiere@iau.edu.sa

Received: 8 August 2022  Accepted: 29 September 2022

Abstract:

Sr_0.8Ni_0.2Fe_12−2xMo_xO₁₉ (x ≤ 0.35) nanohexaferrites (NHFs) were obtained by a sol–gel combustion route. The phase identification was performed through X-ray powder diffraction (XRD), transmission electron microscopy (TEM), and high-resolution transmission electron microscopy (HR-TEM). The morphological and chemical composition analyses were verified by scanning electron microscope (SEM) and energy dispersive X-rays (EDX), respectively. The crystallite size (D_XRD) of all produced samples has been estimated between 31 and 56 nm. Magnetization versus applied magnetic field (M–H) measurements of different products were conducted at 300 K (room temperature, RT) and 10 K, and the results revealed their ferrimagnetic character. Undoped Sr_0.8Ni_0.2Fe₁₂O₁₉ NHFs have the maximum magnetic parameters at both temperatures. 10 K magnetization data such as M_S (saturation magnetization), M_r (remnant magnetization), n_B (magneton number), and H_C (coercivity) belonging to Sr_0.8Ni_0.2Fe₁₂O₁₉ NHFs are M_S,max = 99.6 emu/g, M_r,max = 48.2 emu/g, n_B,max = 18.83 μ_B, and H_C,max = 3406 Oe, respectively. Moreover, the squareness ratio (SQR = M_r/M_S) is 0.489 at RT and 0.484 at 10 K. Those magnitudes assign the single-domain structure with uniaxial crystal anisotropy for this hexagonal product at both temperatures. Some magnetic parameters like coercivities (in a range of (286–475) Oe) and M_r (in a range of (7.8–14.1) emu/g) drop sharply due to the Mo⁶⁺ doping process. Calculated SQR values are between 0.111 and 0.206, which indicate the multi-domain wall structure for NHFs at both temperatures. Undoped Sr_0.8Ni_0.2Fe₁₂O₁₉ NHFs can be classified as magnetically hard materials, while Mo-doped samples can be classified as soft magnetic materials.

Keywords: Sr hexaferrite; Mo substitution; Structure; Morphology; Magnetic properties

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-022-02527-z

Chemical Papers 77 (2) 947–956 (2023)