Effects of dipolar interactions on the magnetic hyperthermia of Zn0.3Fe2.7O4 nanoparticles with different sizes

Tumor-targeted magnetic hyperthermia has recently attracted much attention.Magnetic nanoparticles(NPs) are heat mediator nanoprobes in magnetic hyperthermia for cancer treatment.In this paper,single cubic spinel structural Zn_0.3Fe_2.7O₄ magnetic NPs with sizes of 14 nm-20 nm were synthesized,followed by coating with SiO₂ shell.The SLP value of Zn_0.3Fe_2.7O₄/SiO₂ NPs below 20 nm changes non-monotonically with the concentration of solution under the alternating current(AC) magnetic field of 430 kHz and 27 kA/m.SLP values of all Zn_0.3Fe_2.7O₄/SiO₂ NPs appear a peak value with change of solution concentration.The solution concentrations with optimal SLP value decrease with increasing magnetic core size.This work can give guidance to the better prediction and control of the magnetic hyperthermia performance of materials in clinical applications.     

Enhanced hyperthermia performance in hard-soft magnetic mixed Zn0.5CoxFe2.5−xO4/SiO2 composite magnetic nanoparticles

High quality Zn0.5CoxFe2.5?xO4(x=0,0.05,0.1,0.15)serial magnetic nanoparticles with single cubic structures were prepared by the modified thermal decomposition method,and Zn0.5CoxFe2.5?xO4/SiO2 composite magnetic nanoparticles were prepared by surface modification of SiO2.The magnetic anisotropy of the sample increases with the increase of the doping amount of Co2+.When the doping amount is 0.1,the sample shows the transition from superparamagnetism to ferrimagnetism at room temperature.In the Zn0.5CoxFe2.5?xO4/SiO2 serial samples,the maximum value of specific loss power(SLP)with 1974 W/gmetal can also be found at doping amount of x=0.1.The composite nanoparticles are expected to be an excellent candidate for clinical magnetic hyperthermia.     

Effect of Magnetic Anisotropy on Magnetic Thermal Induction of Mn_(0.3)Zn_(0.3)Co_xFe_(2.4-x)O_4 Nanoparticles

Mn_(0.3)Zn_(0.3)Co_xFe_(2.4-x)O_4 series magnetic nanoparticles are prepared by the high-temperature organic solvent method, and Mn_(0.3)Zn_(0.3)Co_xFe_(2.4-x)O_4@SiO_2 composite nanoparticles are prepared by the reverse microemulsion method. The as-prepared samples are characterized, and the results show that the magnetic anisotropy constant of nanoparticles increases with the cobalt content, and the magnetic thermal induction shows a trend of increasing first and then decreasing. The optimal magnetic thermal induction is obtained at x = 0.12 with a specific loss power of 2086 w/gmetal, which is a bright prospect in clinical magnetic hyperthermia.     

Table-Like Large Magnetocaloric Effect in the Misch Metal RSi Compound

Magnetic properties and the magnetocaloric effect(MCE)of the RSi(R=Ce,Pr,Nd)compounds made of Misch metal(MM)are investigated.Two transitions are found at 12K and 38K.Field variation generated large MCE and two peaks are found in the magnetic entropy change(△S)curves,which correspond to the two transition temperatures.The maximum values of the magnetic entropy changes(△S)are found to be-5.1 J/(kg·K)and-9.3 J/(kg·K)for the field ranges of 0-2 T and 0-5 T,respectively.The large AS as well as ultra-low price of MM make(MM)Si a competitive magnetic refrigerant candidate for low temperature in Eriksson cycle.