Title :
Size-Dependent Magnetic Properties of PtMn Nanoparticles
Author :
Ho, Chien-Hsin ; Lai, Chih-Huang
Author_Institution :
Dept. of Mater. Sci. & Eng., Nat. Tsing Hua Univ.
Abstract :
PtMn nanoparticles have been synthesized by chemical methods. The as-synthesized PtMn nanoparticles show superparamagnetic behavior at room temperature and ferromagnetic behavior at 5 K due to the uncompensated surface spins originating from the finite size effect. Different PtMn sizes were obtained after various temperature annealing processes. The exchange bias and vertical loop shift of PtMn nanoparticles were observed at 5 K in field cooling process and were ascribed to the exchange coupling of ferromagnetic surface spins and the antiferromagnetic core. It was found that the coercivity and exchange bias field were strongly related to the particle size
Keywords :
antiferromagnetic materials; coercive force; ferromagnetism; magnetic annealing; magnetic particles; nanoparticles; particle size; platinum alloys; superparamagnetism; 5 K; PtMn; PtMn nanoparticles; antiferromagnetic core; chemical methods; exchange bias; exchange coupling; ferromagnetic surface spins; field cooling process; particle size; size-dependent magnetic properties; superparamagnetic behavior; temperature annealing processes; vertical loop shift; Annealing; Antiferromagnetic materials; Chemicals; Coercive force; Cooling; Magnetic field measurement; Magnetic hysteresis; Magnetic properties; Nanoparticles; Temperature; Exchange bias; PtMn nanoparticles; size dependent; vertical loop shift;
Journal_Title :
Magnetics, IEEE Transactions on
DOI :
10.1109/TMAG.2006.880110
