TY - JOUR
T1 - Magnetic properties of Fe nano-clusters stabilized at grain boundaries of Yb films
AU - Rojas-Ayala, Chachi
AU - Passamani, E. C.
AU - Litterst, F. J.
AU - Baggio-Saitovitch, E.
PY - 2014/1/1
Y1 - 2014/1/1
N2 - © 2014 AIP Publishing LLC. The temperature dependence of the magnetic properties of Fe nano-sized clusters in (5.0 at.-% Fe)Yb films, prepared by vapor co-deposition, has systematically been investigated using zero-field and in-field Mössbauer spectroscopy as well as AC and DC magnetization measurements. Room temperature Mössbauer spectra reveal two types of Fe clusters, with non-cubic symmetry, located at Yb grain boundaries. Spectra, taken at 4.2-K, show a complex distribution of magnetic hyperfine fields, which can be related to inhomogeneous inter-cluster interactions. In addition, zero-field and in-field Mössbauer experiments indicate that the interactions within the Fe-clusters are predominantly ferromagnetic-like and their average magnetic moments are about 80-μB. As suggested by Mössbauer and AC magnetization data, the Fe-clusters are superparamagnetic above ca. 20-K, while their magnetic behavior below this temperature is that of cluster-glass-like systems with weak inter-cluster interactions. The details of the freezing process as a function of frequency and magnetic field are discussed and magnetic anisotropy constants for these Fe clusters are estimated to be Keff-∼-8-12-×-105-J m-3.
AB - © 2014 AIP Publishing LLC. The temperature dependence of the magnetic properties of Fe nano-sized clusters in (5.0 at.-% Fe)Yb films, prepared by vapor co-deposition, has systematically been investigated using zero-field and in-field Mössbauer spectroscopy as well as AC and DC magnetization measurements. Room temperature Mössbauer spectra reveal two types of Fe clusters, with non-cubic symmetry, located at Yb grain boundaries. Spectra, taken at 4.2-K, show a complex distribution of magnetic hyperfine fields, which can be related to inhomogeneous inter-cluster interactions. In addition, zero-field and in-field Mössbauer experiments indicate that the interactions within the Fe-clusters are predominantly ferromagnetic-like and their average magnetic moments are about 80-μB. As suggested by Mössbauer and AC magnetization data, the Fe-clusters are superparamagnetic above ca. 20-K, while their magnetic behavior below this temperature is that of cluster-glass-like systems with weak inter-cluster interactions. The details of the freezing process as a function of frequency and magnetic field are discussed and magnetic anisotropy constants for these Fe clusters are estimated to be Keff-∼-8-12-×-105-J m-3.
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U2 - 10.1063/1.4901645
DO - 10.1063/1.4901645
M3 - Article
SN - 0021-8979
JO - Journal of Applied Physics
JF - Journal of Applied Physics
ER -