Fine-tuning magnetic and hyperthermia properties of magnetite (Fe3O4) nanoparticles by using ammonia as a reducing agent

چکیده مقاله

The tunable control of heat produced by magnetic nanoparticles (NPs) when placed in an alternating magnetic field can prevent undesirable concurrent heating of healthy tissues for magnetic hyperthermia. Here, magnetite (Fe₃O₄) NPs are synthesized by a co-precipitation method with different concentrations of ammonia (C_A = 7–30 ml) as a reducing agent. By changing C_A, increasing and decreasing trends of structural, morphological and magnetic properties are observed. Superparamagnetic (SPM) behavior of Fe₃O₄ NPs is studied by first-order reversal curve analysis, indicating fine-tuned SPM percentages. By dispersing these NPs in water medium, specific loss power (SLP) is investigated. The variation of SLP as a function of C_A is found to follow that of SPM percentage, reaching a maximum value of 93 W/g for a ferrofluid containing Fe₃O₄ NPs synthesized with C_A = 23 ml. In this case, SPM percentage is maximized to about 60 %, facilitating the heat production by Néel and Brownian mechanisms.