Enhancement of magnetic anisotropy in mechanically attrited Cr 2O 3 nanoparticles

作者：Hajra P; Brahma P; Dutta S; Banerjee S; Chakravorty D^*

来源：Journal of Magnetism and Magnetic Materials, 2012, 324(7): 1425-1430.

DOI：10.1016/j.jmmm.2011.11.064

• Exchange bias
• Magnetic anisotropy

Cr 2O 3 nanoparticles of sizes from 24 to 12 nm were synthesized by mechanical grinding. Magnetic hysteresis loops were observed in the temperature range 5300 K. Zero-field magnetization measurements showed two peaks, at low temperature in the range 3652 K and at high temperature in the range 255290 K. They were found to shift to higher temperatures as the particle size was reduced. This was ascribed due to the enhancement of the effective anisotropy constant with a decrease in particle size. The exchange bias was found to increase as the particle size became smaller. This is believed to arise due to an increase in uncompensated spins as a result of large surface area created.

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