Zn- and (Mn, Zn)-substituted versus unsubstituted magnetite nanoparticles: structural, magnetic and hyperthermic properties

Abstract

In this work, we studied structural and magnetic properties of 18nm-sized Zn-substituted magnetite, 28nm-sized unsubstituted and 17nm-sized (Mn,Zn)-substituted iron oxide nanoparticles, synthesized by thermal decomposition method. Their features were examined by analyzing the X-ray diffraction (XRD) data, 57 Fe Mössbauer spectra and magnetization measurements by SQUID interferometer. The microstructure was inspected comparing different the size and strain broadening models incorporated into Fullprof software. In terms of crystallinity and size dispersion, applied synthesis protocol shows superiority over decomposition of iron oleate and the co-precipitation synthesis route. The saturation magnetization at T=5 K was found to be within the M S =91.2-98.6 Am 2 /kg range, while at 300 K M S of pure and Zn-substituted Fe 3 O 4 nanoparticles is 83.6 and 86.2 Am 2 /kg, respectively.Effective magnetic anisotropy constant K eff , estimated under slow measurements by SQUID, is below 20 kJ/m 3 in all three samples. Some preliminary measurements of the magnetic hyperthermia performance, expressed via Specific Absorption Rate (SAR) value showed that the best heating performances were displayed by 18nm-sized oleic acid-coated Zn 0.13 Fe 2.87 O 4 cubooctahedrons with SAR@425 W/g Fe at H 0 =20 kA/m and f=228 kHz.

Influence of a Magnetic Field on the Growth and Magnetic Properties of Zn0.15Fe2.85O4 Nanoparticle Chains

“…Both cause a decrease in the B/A ratio in the Mossbauer spectrum as the grain size decreases. 32,43 In this work, we have observed that the B/A ratio increases as the grain size increases, which seems to support the above explanation well. Moreover, this result also agrees well with the saturation magnetization of our samples, which increases with increasing grain size (or H syn ), as shown in Figure 6e and discussed later.…”

“…Note that the line width of the B site sextet is much broader than that of the A site, which has been previously observed and is attributed to the change of the nearest neighbor interactions owing to the incorporation of nonmagnetic Zn 2+ . 42,43 In addition, the relative absorption intensity (RAI) ratio B/A reflects the ratio of the overall number of Fe ions between B and A sites, and its increase from 1.85 for ZFO-0 to 2.32 for ZFO-3 might be attributed to the size effect of grains. For zero/low-fieldsynthesized particles, the smaller grains within the particle undergo non-negligible peroxidation, as well as atom disorder at the grain surface and boundaries.…”

D-Alpha-Tocopheryl Poly(ethylene Glycol 1000) Succinate-Coated Manganese-Zinc Ferrite Nanomaterials for a Dual-Mode Magnetic Resonance Imaging Contrast Agent and Hyperthermia Treatments

“…In terms of size dispersion and uniform morphology, applied synthetic protocol in this study showed superiority over co-precipitation [ 30 ], chemical sol-gel combustion [ 31 ], or hydrothermal [ 19 ] synthesis routes. The MZF synthesized by thermal decomposition by acetyacetonate metal precursors with less surfactants may more uniform shape than the acetylacetonate with chloride salts [ 32 ].…”

Recent advances in zinc ferrite (ZnFe2O4) based nanostructures for magnetic hyperthermia applications

“…[12][13][14][15][16] The key parameters that determine nanoparticle heating during MHT include shape, size, saturation magnetization (M s ), coating material, and concentration of nanoparticles, among other. [17][18][19][20][21][22][23] This procedure, which is primarily non-invasive and, thus, has attracted scientists to further advance this research domain, has the potential to modernize future nanomedicine research. In the past two decades, MHT has attracted significant attention because of its ability to destroy malignant tumors when practiced concurrently with traditional chemo and radiotherapy strategies.…”

“…12–16 The key parameters that determine nanoparticle heating during MHT include shape, size, saturation magnetization ( M s ), coating material, and concentration of nanoparticles, among other. 17–23…”