176 ISSN 1061-3862, International Journal of Self-Propagating High-Temperature Synthesis, 2020, Vol. 29, No. 3, pp. 176–180. © Allerton Press, Inc., 2020. Al-Doped Co-Cd Nanoferrites by Solution-Combustion Synthesis: Preparation and Structural Characterization L. C. Shidaganal a, d , A. B. Kulkarni b , S. B. Kapatkar c, *, S. N. Mathad d, **, and R. B. Pujar a a Department of Physics, P.C. Jabin Science College, Hubballi, Karnataka, India b Department of Physics, SKES Govindram Seksaria Science College, Belagavi, India c K.L.E. Technological University, Hubballi, Karnataka, India d Department of Engineering Physics, K.L.E. Institute of Technology, Hubballi, Karnataka, India *e-mail: sbkapatkar@bvb.edu **e-mail: physicssiddu@gmail.com Received May 4, 2020; revised May 16, 2020; accepted May 17, 2020 Abstract—Al-doped Co-Cd ferrites Co 0.4 Cd 0.6 Al x Fe 2–x O 4 (x = 0.1, 0.2, 0.3, 0.4) were prepared by solution- combustion synthesis (SCS) and characterized by XRD, SEM, EDAX, and FTIR. A simple cubic spinel structure of synthesized ferrites with a = 8.496–8.545 Å was confirmed by XRD. The uniform size distribu- tion of ferrite grains was observed in SEM micrographs. The elemental analysis confirmed the presence of all metal ions from the ferrite formula. FTIR spectra showed two absorption bands, υ 1 (568–580 cm –1 ) and υ 2 (413–451cm –1 ), attributed to Me–O vibration modes at tetrahedral and octahedral sites, respectively. Our results may turn interesting to those engaged in combustion synthesis of ferrites. Keywords: solution-combustion synthesis, Al-doped Co–Cd ferrites, structural characteristics DOI: 10.3103/S1061386220030103 1. INTRODUCTION Cubic spinel ferrites AB 2 O 4 [1] find wide practical applications [2]. Cobalt ferrite CoFe 2 O 4 attracts much attention owing to its excellent properties such as rela- tively high saturation magnetization (M s ), high coer- civity (H c ), magnetic anisotropy, chemical stability, and catalytic activity, some of which can also be tuned [3]. Spinel ferrites are good candidates for use in mag- netic recording and microwave applications [4], per- manent magnets [5], magnetic drug delivery [6], high- density information storage [7], in recording heads, antenna rods, loading coils, microwave devices, and core material for power transformers [8]. Ferrite materials can be prepared by a number of methods such as co-precipitation [9], solid-state reac- tions [10, 11], citrate gel process [12], solution com- bustion [13], ball milling [14], and hydrothermal syn- thesis [15]. In this communication, we report on the influence of Al doping on structural and mechanical properties of crystalline Co–Cd spinel ferrites prepared by solu- tion-combustion synthesis (SCS). 2. EXPERIMENTAL AR grade starting materials—Co(NO 3 ) 2 ⋅ 6H 2 O, Cd(NO 3 ) 2 ⋅ 4H 2 O, Al(NO 3 ) 3 ⋅ 9H 2 O, and Fe(NO 3 ) 3 ⋅ 9H 2 O—were taken in stoichiometric amounts, dis- solved in double distilled water, and stirred at 60°C to get uniform solution. A suitable amount of sucrose was added into the mixture. The mixture was then heated until ignition and resultant product was sintered at 800°C [16] for 10 h. The end product was then used to prepare pellets 1 cm in diameter under 10-ton pressure using PVA as binder. These pellets were sintered again at 1000°C for 10 h. The latter ones were characterized by XRD (Bruker AXS D8 diffractometer, Cu Kα radi- ation, JCPDS card 00-022-1086), SEM/EDAX (JEOL Model JSM-6390LV) and FTIR (Thermo Nicolet, Avatar 370). 3. RESULTS AND DISCUSSION 3.1. XRD Analysis XRD patterns of synthesized ferrites are shown in Fig. 1. The peaks matched well with those from JCPDS card 00-022-1086. The reflections observed from the planes (220), (311), (400), (422), (511), (440) and (533) confirm the formation of a cubic spinel structure.