S M Rathod

V D Kulkarni

CiteSeerX

IOSR Journal of Applied Physics (IOSR-JAP)  
e-ISSN: 2278-4861.Volume 9, Issue 1 Ver. I (Jan. – Feb. 2017), PP 78-81 
www.iosrjournals.org 
DOI: 10.9790/4861-0901017881                                          www.iosrjournals.org                                   78 | Page 
 
Dielectric, Electric and Thermal Behavior of La
3+
 doped Co-Zn 
Nanoferrite 
 
V. D. Kulkarni
1*
, S. M. Rathod
2
 
1
Department of Physics, Hutatma Rajguru Mahavidyalaya, Rajgurunagar, Dist-Pune, Pin-410505, MS, INDIA 
*Research Student, Science College, SRTM University, Nanded 
2
 Nanomaterials & Lasers Research Lab, Department of Physics, Abasaheb Garware College, Pune- 411 004, 
MS, INDIA 
 
Abstract: Dielectric, Electric and Thermal properties  of rare earth La3+ material doped in Co0.5Zn0.5 Lax Fe(2-
x)O4 (where x=0.025, 0.050, 0.075, 0.100, 0.125) reaction nanocrystalline ferrites were synthesized by sol-gel 
auto combustion method. The electric, dielectric constant and Thermal properties were investigated. The 
dielectric constants and dielectric loss of the samples was observed between the 100Hz and 5 MHz. The 
resistivities of the prepared samples were measured from 0 Volt to 550 Volts at the constant temperature 200
0
C 
using the Two Probe method. The Thermal properties were characterized by Thermo Gravimetric and 
Differential Thermal Analysis (TGDTA). 
Keywords: Sol-gel method, Co-Zn ferrite, TGDTA, Dielectric constant. 
 
I. Introduction 
The main advantage of sol-gel auto combustion method is an excellent combination of combustion and 
chemical reaction. This method has a good stoichiometric control which gives the fine nano particles [1]. Rani et 
al was used solution combustion method to prepare zinc substituted cobalt nanoferrite, with formula Co(1-
x)ZnxFe2O4 (x = 0.0, 0.1, 0.2, 0.3, 0.4). The electric and dielectric properties were studied. The dc resistivity, 
dielectric constant and dielectric loss of nanoferrite was studied. The dielectric constant and dielectric loss 
tangent was measured in the frequency range between 1 kHz to 1MHz and found that as frequency increases, 
then dielectric constant and dielectric loss tangent decreases [2].  M.K. Shobana was studied synthesis of 
Lithium doped cobalt ferrite nanoparticles using sol–gel combustion Method. The four probe method was used 
for electrical properties. This paper showed that the conductivity of the ferrite sample decreased in increase of 
lithium concentration. The applications of such nanoferrite may be useful in microwave and high frequency 
devices [3]. Ping Hu-et-al was studied the Mn-Zn ferrites which were prepared by the nitrate-citrate auto 
combustion method.   This paper mainly studied the effect of heat treatment on crystalline phase’s formation 
and thermo gravimetric and differential thermal analysis. Mn–Zn ferrites play an important role in biomedicine 
as magnetic carriers for bio separation, enzymes and proteins immobilization [4]. V.V.Awati et al was studied 
the Cu
+2
 substituted Ni-Zn ferrite prepared by auto combustion method. This paper showed that dielectric 
constant and dielectric loss are the frequency dependent. While dielectric constant increases with increase in 
copper content. The copper has good conductivity than nickel [5]. B.A.Aldar et al was studied Ni-Co-Cd Ferrite. 
This paper was observed that resistivity decreases with increase in temperature. The dielectric constant also 
depends upon the temperature [6].The ac conductivity at various frequencies and at different temperatures was 
measured and found to be conductivity increases with increasing frequencies. The dispersion parameters was 
also obtained by graphical method of the Cole–Cole diagram and found to be in the specific temperature range 
[7,8]. The Ni Zn ferrite was synthesized with the help of solid state reaction techniques. The DC resistivity was 
measured by Two Probe Method. The DC resistivity decreases with increase in temperature. The DC resistivity 
is the temperature dependent [9]. The NiCuZn ferrites were synthesized by the citrate precursor method. It 
enhances the properties, so that NiCuZn ferrites may be used in multilayer chip inductors within RF frequency 
range[10]. The Er–Ni substituted strontium hexaferrite was synthesized. The dielectric constant and dielectric 
loss was reported as to decrease with Er–Ni substitution. This paper was recommended that such ferrites can be 
used in microwave devices [11]. 
Therefore, the present work studied the rare earth La
3+
 material substituted in Cobalt-Zinc nanoferrites were 
synthesized using the sol-gel auto combustion method. The behavior of Dielectric Constant, Electric and 
Thermal properties of Cobalt-Zinc nanoferrites was studied. 
 
II. Material And Method 
The sol-gel auto combustion method was used for the synthesis of Co0.5Zn0.5 LaxFe2-xO4 (Where 
x=0.025, 0.050, 0.075, 0.100, 0.125) nanoparticles.  Ferric nitrate (Fe(NO3)3.9H2O), Zinc   nitrate 
(ZnNO3·6H2O),  Cobalt nitrate (CoNO3·6H2O), Citric acid (C6H8O7),  Ammonium  hydroxide   solution 
Dielectric, Electric and Thermal Behavior of La
3+
 doped Co-Zn Nanoferrite 
DOI: 10.9790/4861-0901017881                                          www.iosrjournals.org                                   79 | Page 
(NH4OH)   were   used. All AR grade nitrates and chemicals were used. The Citric acid acts as a fuel. The 
stoichiometric ratio proportion was used for the synthesis. All  chemicals   was dissolved   in distilled  water  
and  were  stirred  till to get the  homogeneous  solution. The ammonium    hydroxide was added drop by drop 
for   pH =7 throughout the stirring process. This chemical solution was stirred constantly for 3 to 4 hours at 100 

C to get sol. This sol becomes a viscous gel after half an hour and auto-combustion takes place. The Cobalt-
Zinc nanoferrite powders were prepared and this powder was sintered at 600 

C for 4 hours. 
 
III. Results And Discussion 
3.1 Dielecric Constant (ε) and Dielecric Loss (Tan δ): 
 The dielectric constant was calculated using the formula 
 
ε = Cd/ε0A 
 
Where C=capacitance in farad, d=thickness in meters, A= cross sectional area of pellet and ε0 – permittivity of 
free space. 
               
 
Fig.1: Variation of Dielectric Constant (ε) with log(f)    Fig.2: Variation  of Dielectric Loss (Tan δ) with  log(f) 
                                                                                                                                     
The dielectric constants (ε) of the prepared (Co0.5Zn0.5 LaxFe2-xO4) (where x = 0.025, 0.050, 0.075, 
0.100 and 0.125) nanocrystals was measured between the 100Hz and 5 MHz. Fig.1 shows that the dielectric 
constant decreases as the frequency increases, this indicates that normal behavior of magnetic material.  
The dielectric loss (Tan δ) of the prepared (Co0.5Zn0.5 LaxFe2-xO4) (where x = 0.025, 0.050, 0.075, 0.100 and 
0.125) nanocrystals was measured between the 100Hz and 5 MHz. Fig.2 shows that dielectric loss (Tan δ) 
versus log (f) graphs. From graphs, it is observed that dielectric loss decreases with increase in frequencies after 
the initial peaks obtained at approximately 600 – 700 Hz. Hence it is the abnormal behavior of the dielectric 
loss. 
 
3.2 D.C. Resistivity:  
The dc resistivity (ρ) of the prepared (Co0.5Zn0.5 LaxFe2-xO4) (where x = 0.025, 0.050, 0.075, 0.100 and 0.125) 
nanocrystals was measured by Two Probe method. The dc resistivity was calculated by the formula 
 
Resistivity (ρ) =AR/L Ohm-m 
 
The resistivity was observed between the voltage 0 Volt and 550 Volts at constant temperature 200
0
C. The 
resistivity of the prepared (Co0.5Zn0.5 LaxFe2-xO4) (where x = 0.025, 0.050, 0.075, 0.100 and 0.125) nanocrystals 
decreases with the voltage increases after 100 Volts shown in Fig.3. The decrease in resistivity may be due 
temperature. 
 
Dielectric, Electric and Thermal Behavior of La
3+
 doped Co-Zn Nanoferrite 
DOI: 10.9790/4861-0901017881                                          www.iosrjournals.org                                   80 | Page 
 
 
Fig.3: Variation  of Resistivity with Voltage 
3.3 Thermal Properties: 
The prepared nanoparticles were characterized by Thermo Gravimetric and Differential Thermal Analysis 
(TGDTA). Fig.4 shows that TG curve, as temperature increases then continuous weight loss. 
Fig.5 shows that initially voltage increases as temperature increases up to 250
0
C. Between temperature 250
0
C 
and 400
0
C, the voltage remains constant. After temperature 400
0
C, voltage decreases it may be due to the weight 
loss. 
 
               
 
Fig. 4: TGDTA of Co0.5Zn0.5 LaxFe2-xO4(x=0.05)                  Fig. 5: TGDTA of Co0.5Zn0.5 LaxFe2-xO4(x=0.05) 
 
IV. Conclusions 
The rare earth La
3+
 material doped in Coo.5Zn0.5 LaxFe2-xO4 (where x=0.025, 0.050, 0.075, 0.100, 0.125) 
reaction nanocrystalline ferrites were synthesized by sol-gel auto combustion method successfully. The 
dielectric constant (ε) decreases with the increase in frequencies, this gives the normal behavior of magnetic 
material. The dielectric loss decreases after the initial peaks obtained at approximately 600 – 700 Hz with 
increase in frequencies, this gives the abnormal behavior of the dielectric loss. The resistivity of the prepared 
nanoferrite decreases with the voltage increases after 100 Volts. The decrease in resistivity may be due 
temperature. The continuous weight loss with increase in temperatures is shown in TGDTA graph. 
 
Acknowledgement 
We are thankful to Science College, Nanded, SAIF, IIT, Powai, Mumbai, Modern College, Ganeshkhind, Pune 
and Abasaheb Garware College, Pune. 
 
References 
[1]. A.A. Sattar, H.M. El-Sayed, K.M. El-Shokrofy, and M.M. El-Tabey, “Improvement of the  magnetic properties of Mn-Ni-Zn Ferrite 
by the non-magnetic Al3+ Ion substitution“, Journal of Applied Sciences, 5, 2005, 162-168. 
Dielectric, Electric and Thermal Behavior of La
3+
 doped Co-Zn Nanoferrite 
DOI: 10.9790/4861-0901017881                                          www.iosrjournals.org                                   81 | Page 
[2]. R.Rani, Gagan Kumar, Batoo Khalid Mujasam, M. Singh M, “Electric and Dielectric Study of Zinc Substituted Cobalt Nanoferrites 
Prepared by Solution Combustion Method”, American Journal of Nanomaterials, 1(1), 2013, 9-12. 
[3]. M.K.Shobana,” Electrical and structural studies of lithium doped cobalt ferrite”, Journal of Physics and Chemistry of Solids, 73, 
2012, 1040–1043. 
[4]. P. Hu, H. Yang , D.Pan , H. Wang , J. Tian , S. Zhang , X.Wang , A. A. Volinsky , “Heat treatment effects on microstructure and 
magnetic properties of Mn–Zn ferrite powders”, Journal of Magnetism and Magnetic Materials, 322, 2010,173–177. 
[5]. V.V.Awati, D.H.Bobade, Mrs S.D. Kulkarni, S.M.Rathod, “Structural, Dielectric and Magnetic Behavior of Cu+2 substituted Ni-Zn 
ferrite by Auto-combustion Technique”, International Journal of Engineering Research and Applications, 2(6), 2012, 482-489. 
[6]. B.A.Aldar, R.K.Pinjari, N.M.Burange, “Electric and Dielectric Behavior of Ni-Co-Cd Ferrite”, IOSR Journal of Applied Physics, 
6(4) Ver.II, 2014, 23-26. 
[7]. A.M. Abo El Ata, M.A. Ahmed, “Dielectric and AC conductivity for BaCo2~xCuxFe16O27 ferrites”, Journal of Magnetism and 
Magnetic Materials, 208, 2000, 27-36. 
[8]. Nisha J. Tharayil, S. Sagar, R. Raveendran, A.V. Vaidyan, “Dielectric studies of nanocrystalline nickel–cobalt oxide”, Science 
Direct, Physica B 399, 2007, 1–8 
[9]. Abdul Samee Fawzi, A.D. Sheikh, V.L. Mathe, “Structural, dielectric properties and AC conductivity of Ni (1−x)ZnxFe2O4 spinel 
ferrites”, Journal of Alloys and Compounds ,502 2010, 231–237. 
[10]. M. C. Dimri , A. Verma , S. C. Kashyap , D.C. Dube, O.P. Thakur , Chandra Prakash ,”Structural, dielectric and magnetic 
properties of NiCuZn ferrite grown by citrate precursor method”. Materials Science and Engineering, B 133, 2006, 42–48. 
[11]. Muhammad Naeem Ashiq , Muhammad Javed Iqbal , Muhammad Najam-ul-Haq , Pablo Hernandez Gomez , Ashfaq Mahmood 
Qureshi, “Synthesis, magnetic and dielectric properties of Er–Ni doped Sr-hexaferrite nanomaterials for applications in High 
density recording media and microwave devices”, Journal of Magnetism and Magnetic Materials 324,2012, 15–19. 
 


Dielectric, Electric and Thermal Behavior of La 3+ doped Co-Zn Nanoferrite

http://citeseerx.ist.psu.edu/viewdoc/download;jsessionid=D43244F3DC11F02FBD1F461220A14429?doi=10.1.1.1039.4438&rep=rep1&type=pdf

Dielectric, Electric and Thermal Behavior of La 3+ doped Co-Zn Nanoferrite

Abstract

Similar works

Full text

Available Versions

CiteSeerX