Title :
MBE-Grown Fe Magnetic Quantum Dots in ZnS Matrix
Author :
Lok, S.K. ; You, B. ; Zhang, B. ; Zhang, X.X. ; Sou, I.K. ; Wong, G.K.L.
Author_Institution :
Hong Kong Univ. of Sci. & Technol., Kowloon
fDate :
6/1/2007 12:00:00 AM
Abstract :
A multilayer magnetic quantum dot sample containing 5 layers of Fe quantum dots (QDs) embedded in six layers of ZnS spacer was grown by molecular beam epitaxy (MBE). High-resolution transmission electron microscopy (HRTEM) observations reveal that the Fe QDs are single crystalline with spherical shape of diameters around 3 to 4 nm and area density of 1.5times1012 cm-2. Its zero-field cooled (ZFC) and field cooled (FC) curves measured at low field (100 Oe) show the magnetic relaxation effect with a blocking temperature around 26 K. The hysteresis loop measured at 5 K shows a coercivity of 83 Oe, confirming the slow relaxation process and coercivity enhancement attributed to the nanoparticle nature of the sample
Keywords :
coercive force; crystal microstructure; ferromagnetic materials; iron; magnetic hysteresis; magnetic moments; magnetic multilayers; magnetic particles; magnetic relaxation; molecular beam epitaxial growth; nanoparticles; quantum dots; transmission electron microscopy; 5 K; Fe; ZnS; coercivity; high-resolution transmission electron microscopy; hysteresis loop; magnetic quantum dots; magnetic relaxation effect; molecular beam epitaxy; multilayer; nanoparticle; zero-field cooled curves; Coercive force; Crystallization; Iron; Magnetic field measurement; Magnetic multilayers; Molecular beam epitaxial growth; Quantum dots; Shape; Transmission electron microscopy; Zinc compounds; Magnetic anisotropy; quantum dots;
Journal_Title :
Magnetics, IEEE Transactions on
DOI :
10.1109/TMAG.2007.893859
