{'fraction_non_alphanumeric': 0.03162650602409638, 'fraction_numerical': 0.030873493975903613, 'mean_word_length': 5.746192893401015, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Effect of Zn nonmagnetic element doping and a polyvinyl pyrrolidone shell layer on the superparamagnetism and stability properties of magnetic nanoparticles

Zn x Fe1−x Fe2O4 nanoparticles (x = 0.0–0.25) were synthesized by the coprecipitation method. Their microstructure was investigated by X-ray diffraction with Rietveld refinement software, energy-dispersive X-ray spectroscopy, transmission electron microscopy, and Fourier transform infrared absorption spectroscopy. Their thermal, magnetic properties were investigated by thermogravimetric analysis and vibrating-sample magnetometer. The nanoparticles exhibited superparamagnetic properties, with a maximum saturation magnetization of 80.2 emu g−1 in H = 11 000 Oe at room temperature for sample with x = 0.20. The Zn nonmagnetic element content is related to the cation distribution in the superlattices and magnetic moment of the particles. The Zn0.15Fe0.85Fe2O4 nanoparticles were coated with polyvinyl pyrrolidone (PVP) with different PVP mass. Their core–shell structure was investigated, the results showed that their chemical stability and saturation magnetization were greater than those of pure Fe3O4. PVP has biological compatibility; thus, Fe0.85Zn0.15Fe2O4/PVP0.75 nanocomposite has the potential to be widely used in medical biology, science and technology.