Core-Shell Effect on the Magnetic Properties in Superparamagnetic Nanosystems

3 Core-Shell Effect on the Magnetic Properties in Superparamagnetic Nanosystems 

Low-temperature Mossbauer spectra with (a) no applied field (b) field applied along the -y-ray direction (c) field applied perpendicular to y-ray direction after cooling down to 5 K with no applied field (d) field applied perpendicular to y-ray direction after cooling down to 5 K in the presence of 5T field. (Reprinted with permission from Ref. 29. Copyright (2009) by the American Physical Society.) 

TABLE 21.2 Parameters Obtained from Mossbauer Fitting Using Core-Shell Model for Various Measurements (Field Applied 5T) [29]  

TABLE 21.3 Canting Effects from Shell for Various Measurements [29]  

From the value of Tb and particle size V, the anisotropy energy K, the energy barrier A for rotation on applying a field H, and anisotropy field Hk can be estimated using the following expressions [31] 

---