Dipolar and anisotropy effect on dextran coated Cu doped ferrite for magnetic hyperthermia applications.

• Cu x Fe 3-x O 4 with (x = 0.15, 0.31, and 0.47) nanoparticles were synthesized and coated with biopolymers (dextran) using the solvo-thermal route. • Lower coercivity (H c) and anisotropy were observed at room temperature implying nearly superparamagetic behavior. • The self-heating efficiency of uncoated and coated nanoparticles were analysed by taking into account the Brownian and Néel spin relaxations. It was concluded that after dextran coating, the temperature was controlled and that Néel relaxation was dominant on SAR. • The study also demonstrated that the dipolar interaction influenced the Néel relaxation mechanism which was important in the heat generation mechanism of the MNPs. The dipolar interaction and magnetic anisotropy effect are the key parameters to tune the self-heating effect of magnetic nanoparticles (MNPs). In this paper, we investigate the impact of Cu2+ doped Fe 3 O 4 and dextran coated nanoparticles (Cu x Fe 3-x O 4 with x = 0.15, 0.31, and 0.47) on thermal properties using specific absorption rate measurements (SAR). We look into the prospect of using dipolar and anisotropy effects to increase or decrease the heat released by magnetic nanoparticles, potentially boosting hyperthermia applications. Magnetic nanoparticles with an average particle size of 12–20 nm were observed via TEM. The influence of Cu2+ doping on the structural and magnetic properties of the samples was studied using a vibrating sample magnetometer (VSM). The effective anisotropy calculated for x = 0.15 and x = 0.47 were 5.5 and 4.4 j/m3 respectively. It was shown that increasing the copper doping reduced the effective anisotropy, lowering the SAR values. The SAR value obtained for x = 0.15 and dex-x = 0.15 were 787 and 591 W/g respectively. The uncoated Cu x Fe 3-x O 4 nanoparticles achieved hyperthermia temperatures (42–48 °C) much faster than the dextran-coated samples. Eventually temperature can be adjusted to the desired hyperthermia temperature range by altering the sample and Cu2+ concentration. The dextran coating has been shown to dramatically reduce SAR values while still assisting in magnetic hyperthermia temperature regulation. The study also demonstrated that the dipolar interaction influenced the Néel relaxation mechanism which was important in the heat generation mechanism of the MNPs [ABSTRACT FROM AUTHOR]