Evolution of Magnetic Properties of ${\hbox{CaO}}\hbox{-}{\hbox{P}}_{2}{\hbox{O}}_{5}\hbox{-}{\hbox{Na}}_{2}{\hbox{O}}\hbox{-}{\hbox{Fe}}_{2}{\hbox{O}}_{3}\hbox{-}{\hbox{SiO}}_{2}$ Glass Upon Heat Treatment

Abstract

Magnetic hysteresis loss and the resulting local heating in implanted thermoseed (magnetic biocompatible material) can be used to selectively destroy cancerous tissue. We have prepared magnetic bioglass ceramics (MBC) by annealing 41CaO·44 SiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> ·4P <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">5</sub> ·8Fe <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> ·3Na <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O glass at temperatures ( TA) ranging from 750 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">°</sup> C to 1150 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">°</sup> C for 1 h. X-ray diffraction patterns confirm the presence of bone mineral (hydroxyapatite and wollastonite) and magnetite ( Fe <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> ) phases in nanocrystalline form in the MBCs. Average crystallite size ( d <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">av</sub> ) of all the phases increased with increasing T <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">A</sub> . Magnetization ( M-H) curves of all MBCs were recorded up to 20 kOe at 300 K to understand the evolution of magnetism in the nonmagnetic glass upon heat treatment. Magnetic properties correlated with d <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">av(magnetite)</sub> for samples annealed up to 1050 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">°</sup> C. Electron paramagnetic resonance study was carried out to understand the behavior of sample annealed at 1150 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">°</sup> C and the evolution of magnetic properties in the MBCs. This study also reveals a methodology to control the magnetic properties of this MBC and its potential application in hyperthermia treatment of bone cancer.