Nanoparticles of Ni1−xCux alloys for enhanced heating in magnetic hyperthermia

Abstract

In this work we present a method to produce non-aggregated and monodispersed NiCu alloys nanoparticles embedded in chitosan matrix. The refinements of the diffractograms show Ni1−xCux nanoparticles with 2≤ x ≤50. The electron microscopy analysis shows particles with sizes ranging from 11 nm to 20 nm. Magnetization studies at temperatures above the Curie transition reveal the presence of the Griffiths phase which indicates the formation of Ni rich clusters. The results at 5 K show enhanced effective magnetic anisotropies and effective magnetic moments increasing with Ni nominal concentration. The stability of samples stored in air after several months was verified. The system exhibits promising efficiency for magnetic hyperthermia with a specific loss power of up to 5.86 W/g at low field and frequency, and with a maximum temperature rising, ΔT, of 26 °C.