Low‐temperature synthesis of single‐domain Sr‐hexaferrite particles by solid‐state reaction route

Sr‐hexaferrite particles have been synthesized by conventional solid‐state reaction route at low temperatures by boron addition that is used as an inhibitor for crystal growth. The effect of boron concentration on the structural, magnetic and electrical properties of Sr‐hexaferrite particles are investigated by X‐ray crystallography, scanning electron microscopy, magnetization and conductivity measurements. Saturation magnetization of Sr‐hexaferrite increases up to 1 wt% boron addition, while coercivity becomes maximum with a boron amount of 2 wt%. Then, both magnetic parameters start to decrease with higher boron concentrations. Single‐domain and single‐phase powders have been obtained in the sample containing 1 wt% of boron that is sintered at 1050 °C. Impedance spectroscopies reveal that the dc conductivity increases tremendously with boron addition, while the ac conductivity increases with elevated temperature. The ac conductivity obeys roughly the power law of angular frequency in which tendencies change with temperature at low and medium temperature. Furthermore, higher contents of the dopant over approximately 2.0 wt% cause its temperature independency at higher frequencies. These are due to the grain size and secondary phase of hexaferrites that increases with the increase in boron amount.

[1]  D. A. Dunnett.  Classical Electrodynamics , 2020, Nature.

[2]  A. Khater,et al.  Magnetic properties of 2D nano-islands I: Ising spin model , 2011 .

[3]  M. Toprak,et al.  Synthesis, dielectric and magnetic characteristics of poly(1-vinyl-1,2,4-triazole) (PVTri)-barium hexaferrite composite , 2011 .

[4]  H. Sözeri,et al.  Improvement in magnetic properties of La substituted BaFe12O19 particles prepared with an unusually low Fe/Ba molar ratio , 2011 .

[5]  M. Toprak,et al.  Synthesis and characterization of poly(1-vinyl-1,2,4-triazole) (PVTri)–barium hexaferrite nanocomposite , 2011 .

[6]  M. Anis-Ur-Rehman,et al.  Variation in structural and dielectric properties of co-precipitated nanoparticles strontium ferrites due to value of pH , 2011 .

[7]  E. Verwey,et al.  Cation arrangement in a few oxides with crystal structures of the spinel type , 2010 .

[8]  H. Sözeri.  Effect of pelletization on magnetic properties of BaFe12O19 , 2009 .

[9]  M. Toprak,et al.  l-lysine coated iron oxide nanoparticles: Synthesis, structural and conductivity characterization , 2009 .

[10]  A. Maqsood,et al.  Structural, magnetic and electrical properties of cobalt ferrites prepared by the sol–gel route , 2008 .

[11]  M. Iqbal,et al.  Physical and electrical properties of Zr–Cu substituted strontium hexaferrite nanoparticles synthesized by co-precipitation method , 2008 .

[12]  B. Jeyadevan,et al.  Influence of thermal annealing on the dielectric properties and electrical relaxation behaviour in nanostructured CoFe2O4 ferrite , 2007 .

[13]  Yeow-Beng Gan,et al.  Magneto‐Dielectric Properties of Mg–Cu–Co Ferrite Ceramics: II. Electrical, Dielectric, and Magnetic Properties , 2007 .

[14]  K. Bamzai,et al.  Dielectric characteristics of substituted M-type strontium hexaferrite crystals and their modifications on swift heavy ion irradiation , 2007 .

[15]  K. Rao,et al.  Electrical properties of In3+ and Cr3+ substituted magnesium–manganese ferrites , 2005 .

[16]  J. Takada,et al.  Development of nanograined hexagonal barium ferrite thin films by sol–gel technique , 2005 .

[17]  R. Pullar,et al.  Crystallisation of hexagonal M ferrites from a stoichiometric sol–gel precursor, without formation of the α-BaFe2O4 intermediate phase , 2002 .

[18]  M. Emura,et al.  Magnetic properties of coprecipitated barium ferrite powders as a function of synthesis conditions , 2000 .

[19]  W. Song,et al.  Properties of BaFe12O19 films prepared by laser deposition with in situ heating and post annealing , 2000 .

[20]  John Wang,et al.  Improving the magnetic properties of hydrothermally synthesized barium ferrite , 1999 .

[21]  T. Abbas,et al.  STUDY OF SINTERING BEHAVIOR AND ELECTRICAL PROPERTIES OF Cu-Zn-Fe-O SYSTEM , 1995 .

[22]  S. Suib,et al.  Manganese Oxide Octahedral Molecular Sieves: Preparation, Characterization, and Applications , 1993, Science.

[23]  S. Ram.  Crystallisation of BaFe12O19 hexagonal ferrite with an AID of B2O3 and the effects on microstructure and magnetic properties useful for permanent magnets and magnetic recording devices , 1989 .

[24]  S. Ram,et al.  Effect of nucleating agents on the crystallisation behaviour of barium hexaferrite in a borate glass , 1986 .

[25]  Lars Eriksson,et al.  TREOR, a semi-exhaustive trial-and-error powder indexing program for all symmetries , 1985 .

[26]  B. Shirk.  Ba2Fe6O11: A new metastable compound , 1970 .

[27]  A. Cochardt.  MODIFIED STRONTIUM FERRITE, A NEW PERMANENT MAGNET MATERIAL , 1963 .

[28]  C. G. Koops.  On the Dispersion of Resistivity and Dielectric Constant of Some Semiconductors at Audiofrequencies , 1951 .

[29]  H. Erkalfa,et al.  The effect of B2O3 addition on the direct sintering of barium hexaferrite , 1994 .

[30]  H. Kojima,et al.  Chapter 5 Fundamental properties of hexagonal ferrites with magnetoplumbite structure , 1982 .

[31]  A. Gadalla,et al.  Effect of some additions on the sinterability and magnetic properties of barium hexaferrite , 1976 .

[32]  Karl Willy Wagner,et al.  Zur Theorie der unvollkommenen Dielektrika , 1913 .