Abstract
A simple and unified model, which is based on the energy-equilibrium criterion between the spin-spin exchange interactions and the thermal vibration energy of atoms at the transition temperature and a size-dependent Debye temperature function , has been established for the size, dimension, and interface effects on the Curie temperature and the Néel temperature of low-dimensionally ferromagnetic and antiferromagnetic nanocrystals, where denotes the diameter of nanoparticles and nanorods or the thickness of thin films. In terms of this model, and functions are predicted to increase or decrease with dropping , depending on the interaction strength at the film/substrate interface when the interface exists. The predicted results are consistent with available experimental measurements for Fe, Co, Ni, Gd, Ho, , , , , , CoO, NiO, and CuO low-dimensional nanocrystals.
- Received 27 February 2006
DOI:https://doi.org/10.1103/PhysRevB.73.224444
©2006 American Physical Society