关键字：Magnetite; Superparamagnetism; Single crystal; Porous; Molecular field theory
摘要：In this work, sub-millimeter-sized magnetite porous single crystals were found to exhibit unique superparamagnetism rather than the known ferrimagnetism. This superparamagnetism was intimately related to the hydrothermal formation process, during which high lattice stress of ca. 6 GPa and large lattice strain of ca. -1.21 x 10(-2) would change the exchange constants of alpha, beta, and nu to concurrently meet criterions of (i) nu(1) = nu(2) = beta, (ii) alpha(1) = alpha(2) = alpha, and (iii) alpha beta = 1. These criterions, deduced from the molecular-field theory, were proposed to be the general transition conditions for any ferrimagnetic material exhibiting superparamagnetism when their size was beyond their superparamagnetic size limit. (C) 2016 Elsevier B.V. All rights reserved.
卷号：380
期号：41
是否译文：否