Investigation of Structural Dielectric and Magnetic Properties of Transition Metals Doped Cobalt Ferrite Nanostructure

Abstract

IV newlineABSTRACT newlineCobalt ferrite (CoFe2O4) is well known for its high coercivity, excellent chemical newlinestability, and moderate saturation magnetization, which make it a promising material newlinefor high-frequency device applications. In the present study, pristine CoFe2O4 and its newlinetransition-metal-doped derivatives (Bi, Mn, Ni, and Cr) have been synthesized at newlinedifferent concentrations (x = 0, 0.05, 0.10, 0.15, and 0.20 wt.%) using the sol gel newlineauto-combustion method. The structural, dielectric, magnetic, and magnetodielectric newlinecharacteristics of all the prepared samples have been examined to assess newlinetheir potential for high-frequency applications. Phase formation for all compositions newlinehas been confirmed through X-ray diffraction analysis, while the surface morphology newlineof the specimens has been investigated using field-emission scanning electron newlinemicroscopy (FESEM). Pure CoFe2O4 at elevated temperature (350°C) exhibits a newlinedielectric constant of ~1400, dielectric loss ~87 at 100 Hz. In addition, it shows newlineimpedance (Zand#8242;) of around 600 and#937; at 100Hz, high coercivity (1939 Oe), and magnetodielectric newline(MD) response of ~2% at 1.3 T at room temperature. Upon doping, newlinesignificant modifications in the overall properties are observed for all the doped newlinecounterparts as compared to pure CoFeand#8322;Oand#8324;. CoBi0.20Fe1.80O4 shows a very high newlinedielectric constant (and#949;and#8242; and#8776; 5.47×108), low dielectric loss (2.5) at 350°C at 100 Hz. newlineImpedance value also significantly increases and magnetic study reveals decrement newlinein coercivity for this specimen. Among all other doped materials CoMn0.20Fe1.80O4, newlineCoNi0.20Fe1.80O4, CoCr0.20Fe1.80O4 specimens also show higher dielectric constant, newlinelower loss and lesser coercivity as compared to pure cobalt ferrite. Results confirm newlinethat transition metal substitution strongly influences dielectric response, impedance, newlineand magneto-dielectric coupling in CoFe2O4. Thus, controlled doping provides an newlineeffective strategy to optimize cobalt ferrite for advanced high-frequency newlineapplications, including transformers, inductors, and microwave absorbers. newlineKeywords: X - R a y d i f f r a c t i o n , R ama n s p e c t r o s c o p y , Mo r p h o l o g y , newlineDi e l e c t r i c b e h a v i o r , Imp e d a n c e , C o e r c i v i t y , Ma g n e t o - d i e l e c t r i c newlinep r o p e r t i e s , S o l g e l a u t o - c omb u s t i o n me t h o d , T r a n s i t i o n me t a l newlined o p i n g ( B i , Mn , Ni , Cr ) newline