In this article, we report the magnetic properties of surfactant coated g -Fe2O3 nanoparticles which are pressed under different pressures. With increasing pressure, the sample volume decreases, density increases, and a 55% density change has been achieved. The blocking temperature is increased from 50 to 80 K. Analyzing the data of blocking temperature versus densities, which exhibits linear relationship, and comparing the magnetic properties, the increase in blocking temperature is understood in terms of increased magnetic interactions between neighboring nanoparticles, which is due to the reduced average interparticle distance by the applied pressure. © 2000 American Institute of Physics.
Dai, Jianbiao; Wang, Jian-Qing; Sangregorio, Claudio; Fang, Jiye; Carpenter, Everett; and Tang, Jinke (2000). "Magnetic coupling induced increase in the blocking temperature of γ- Fe 2 O 3 nanoparticles." JOURNAL OF APPLIED PHYSICS 87.10, 7397-7399.