Nanosize particles (average size ∼12 nm) of mixed ferrite were prepared by the hydrothermal precipitation route and studied using x-ray diffraction, transmission electron microscopy, differential scanning calorimetry, magnetization measurements, and Mössbauer spectroscopy. The as-prepared sample was largely ferrimagnetic and, as the sample was annealed at temperatures above 250 °C, it gradually became superparamagnetic. This unexpected behavior is explained by assuming that the cation distribution in the nanosize as-prepared sample is in a metastable state and, as the sample is heated, this distribution changes to a more stable state while the grain size remains nearly the same.
Appearance of superparamagnetism on heating nanosize
Chandana Rath, N. C. Mishra, S. Anand, R. P. Das, K. K. Sahu, Chandan Upadhyay, H. C. Verma; Appearance of superparamagnetism on heating nanosize . Appl. Phys. Lett. 24 January 2000; 76 (4): 475–477. https://doi.org/10.1063/1.125792
Download citation file: