Magnetic and magnetothermal studies of pure and doped gadolinium suicide nanoparticles for self-controlled hyperthermia applications

• Published in: Journal of magnetism and magnetic materials Vol. 449; p. 137
• Main Authors: Alnasir, M Hisham, Awan, MS, Manzoor, Sadia
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier BV 01.03.2018
• Subjects: Absorption; Biomedical materials; Coercivity; Curie temperature; Demagnetization; Electric arc melting; Electron microscopy; Ferrites; Ferromagnetism; Gadolinium; Gadolinium oxide; Gadolinium silicide; Hyperthermia; Intermetallic compounds; Magnetic fields; Magnetic properties; Nanoparticles; Scanning electron microscopy; Studies
• ISSN: 0304-8853; 1873-4766

We report on magnetic and magnetothermal properties of undoped and doped gadolinium silicide (Gd5Si4) nanoparticles with the objective of simultaneously attaining high specific absorption rate (SAR) and low Curie temperature (TC) suitable for self-controlled hyperthermia applications for which TC ~ 315-320 K. Pellets of doped gadolinium silicide Gd5(Si1-xGex)4 and (Gd1-xRx)5Si4 with R = Ho, Nd and Er and 0 ≤ x ≤ 0.35 were made by arc melting and reduced to nanoparticulate form by surfactant assisted ball milling. Structural and morphological studies were done using X-ray diffraction and scanning electron microscopy respectively. All samples show soft magnetic properties. At low fields there is a ferromagnetic to paramagnetic transition that reduces remanance and coercivity to zero making these materials very attractive for biomedical applications. Zero-field-cooled thermal demagnetization measurements showed that TC of these nanoparticles can be lowered to lie within the limits required for self-controlled hyperthermia by varying the dopant concentration. Specific absorption rates (SAR's) were obtained from magnetothermia measurements made in an ac magnetic field of amplitude 10 Oe and frequency 300 kHz. We have identified samples that have SAR values larger or comparable to those of magnetite and several ferrite nanoparticles, while having Curie temperatures that are low enough for self controlled hyperthermia applications.