174 ISSN 1061-3862, International Journal of Self-Propagating High-Temperature Synthesis, 2018, Vol. 27, No. 3, pp. 174–179. © Allerton Press, Inc., 2018. Structural, Electrical, and IR Properties of Cu x Co 1–x Fe 2 O 4 (x = 0, 0.4, 1.0) Prepared by Solid-State Method 1 A. S. Pujar a , A. B. Kulkarni b , S. N. Mathad c, *, C. S. Hiremath d , M. K. Rendale e , M. R. Patil f , and R. B. Pujar d a Department of Physics, R.L. Science Institute, Belagavi, 590001 India b Department of Physics, Jain College of Engineering, Belagavi, 590014 India c K.L.E. Institute of Technology, Hubballi, 580030 India d P.G. Studies in Physics, P.C. Jabin Science College, Hubballi, Karnataka, 580031 India e Department of Engineering Physics, K.L.S. Gogte Institute of Technology, Belagavi, 590008 India f S.S. Arts College and T.P. Science Institute, Sankeshwar, 591313 India *e-mail: physicssiddu@gmail.com Received December 14, 2017 Abstract—The effect of copper doping on cobalt ferrites Cu x Co 1–x Fe 2 O 4 (x = 0, 0.4, 1.0) prepared by solid- state method was studied in detail. According to XRD results, the Co–Cu ferrites calcined at 800°C exhibited better crystallinity. Average crystallite sizes varied within the range 18–29 nm. The infrared spectra revealed two principal absorption bands, the high-frequency one ν 1 around 600 cm −1 and the low-frequency one ν 2 around 400 cm −1 , attributed to stretching vibrations of the oxygen–metal bond in the tetrahedral (A) and octahedral (B) sites in the spinel lattice, respectively. The electrical properties of the material were semicon- ducting in their character. The results were used to obtain the following parameters: force constants for tetra- hedral (K t ) and octahedral sites (K o ), Young’s modulus (E), rigidity modulus (G), bulk modulus (B), micro strain (ε), Debye temperature (Θ D ), X-ray density (ρ X ), dislocation density (ρ D ), transverse (V t ) and longi- tudinal (V l ) wave velocities. Keywords: Co–Cu ferrites, XRD, FTIR, electric properties DOI: 10.3103/S1061386218030081 1. INTRODUCTION Ferrites powders or ceramic bodies exhibit fer- rimagnetic behavior caused by the presence of iron oxides. In the spinel structure of the general formula AB 2 O 4 there are twice as many octahedral (B) than tetrahedral (A) sites. If M 2+ occupies only the A sites, the spinel is normal; if it occupies only the B sites, the spinel is inverse [1]. Spinel ferrite nanoparticles are potential candidates for various applications in view of their electronic, optical, electrical, and magnetic properties. Ferrites are also dielectric materials highly useful in microwave applications, high quality filters, rod antennas, radio frequency circuits, transformer cores, and read/write heads for high-speed digital tapes [2, 3]. Cobalt ferrite is a significant ferromag- netic material due to its high electrical resistance and low-eddy current losses [4]. Earlier, Co–Ni ferrites with a grain size of 14–21 nm were prepared by chem- ical co-precipitation technique [5]. Copper ferrite with a normal and inverse spinel structure with enhanced magnetization was studied in [6]. Struc- tural, magnetic and electrical properties Zn-doped copper ferrites prepared by conventional solid-state technique were reported in [7]. The behavior of lattice constant, grain size, sintered density, X-ray density, porosity and resistivity as a function of zinc concen- tration was explored in [8]. Various methods have been suggested for the synthesis of ferrites [9], such as co- precipitation [10, 11], sol–gel [12], solution-combus- tion technique [13], hydrothermal [14], solvothermal [15], and solid-state methods [16, 17]. The aim of the present work was the synthesis of Cu x Co 1–x Fe 2 O 4 ferrites (x = 0, 0.4, 1.0) by low-cost solid-state method and their characterization by XRD, FTIR, and electrical measurements. 2. EXPERIMENTAL In our experiments, we used cobalt ferrite, copper ferrite, and Cu 0.4 Co 0.6 Fe 2 O 4 prepared by solid-state method. The desired composition is obtained by adopting stoichiometric amounts of cobalt oxide, cuprous oxide, and ferric oxide followed by their grinding for 4 h in an agate mortar in acetone medium. 1 The article is published in the original.