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Moyo, T.

doi:10.1088/0953-8984/8/45/023

Cited by 3 publications

(2 citation statements)

References 17 publications

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“…However, in the new version the temperature dependence of coercivity had to be explained by a new concept: the lattice parameter increases with increasing temperature because of thermal expansion, decreasing the size of the Fe-rich clusters. The very rapidly decreasing coercive field by hydrogen doping of Fe-rich Fe-Zr alloys are explained similarly by the introduced lattice distortions [10].…”

Section: F Kiss Et Almentioning

confidence: 83%

Study of the magnetic viscosity of amorphous Fe - Zr alloys in the spin-glass state

Kiss¹,

Kemény²,

Vincze³

1997

J. Phys.: Condens. Matter

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Magnetic viscosity was measured for amorphous Fe 100−x Zr x (7 x 12) alloys in the spin-glass state as a function of magnetic field (0 < H < 500 Oe) and temperature (4.2 < T < 60 K). The viscosity field, H v , deduced from these measurements is independent of H and decreases with increasing temperature as (1/T) 2.0±0.3 for all the alloys. The activation volume, V a , calculated from H v varies with the temperature as T 3.0±0.3. The reduced coercivity, h c = H c /2πM s (H c being the coercivity and M s the saturation magnetization) as a function of D a , the characteristic size calculated from the activation volume, falls approximately to a common curve for all the alloys. This dependence decreases with increasing D a as (1/D a) 2.0±0.2. Such a size dependence of the coercivity hints at a curling-type nucleation mechanism of domains in the spin-glass state of the amorphous Fe-rich Fe-Zr alloys.

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Section: F Kiss Et Almentioning

confidence: 83%

Study of the magnetic viscosity of amorphous Fe - Zr alloys in the spin-glass state

Kiss¹,

Kemény²,

Vincze³

1997

J. Phys.: Condens. Matter

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show abstract

“…In order to explain the temperature dependence of coercivity in the new version, a new concept had to be introduced: the lattice parameter increases with increasing temperature because of thermal expansion, decreasing the size of the Fe-rich clusters. Hydrogen doping of Fe-rich amorphous Fe-Zr alloys decreases very rapidly the coercive field, which are similarly explained by the introduced lattice distortions [21]. Both versions of the model result in an exponential increase of the coercivity, H c , with decreasing temperature, which is related to the upper tail of the assumed Gaussian distribution for the Fe concentration [4].…”

Section: Introductionmentioning

confidence: 82%

Influence of the critical Fe atomic volume on the magnetism of Fe-rich metallic glasses evidenced by pressure-dependent measurements

et al. 2016

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Despite the intensive studies for decades, it is still not well understood how qualitatively different magnetic behaviors can occur in a narrow composition range for the Fe-rich Fe-transition metal (TM) amorphous alloys. In this study of amorphous Fe 100−x Zr x (x = 7, 9, 12) metallic glasses, normal ferromagnetism (FM) is found at 12 % Zr where only the FM-paramagnetic (PM) transition is observed at the Curie temperature, T C . In contrast, spin-glass (SG)-PM transition at a temperature, T g , called SG temperature, is only observed at 7 % Zr, while in the transient re-entrant composition range (x = 8−11), an SG-FM transition at a temperature, T f , called spin-freezing temperature, is also observed at low temperature besides the normal FM-PM transition at T C . In order to understand this unusual behavior, a detailed characterization of pressure (atomic volume), composition, and temperature dependence of the magnetic properties is coupled with high pressure synchrotron x-ray diffraction determination of the pressure dependence of the atomic volume. The results on Fe 100−x Zr x (x = 7, 9, 12) are compared to those obtained for the FM Co 91 Zr 9 metallic glass not showing any kind of anomalous magnetic properties. It is confirmed that the unusual behavior is caused by a granularlike magnetic structure where weakly coupled magnetic clusters are embedded into a FM bulk matrix. Since the mechanism of the magnetization reversal was found to be of the curling type rather than homogeneous rotation, the energy barrier determining the blocking temperature of the clusters is calculated as AR, where A is the exchange constant and R is the cluster size, in contrast to the usual characterization of the energy barrier by KV where K is the anisotropy energy and V is the cluster volume. The volume fraction of the FM part is a fast changing function of the bulk composition: Almost 100% FM fraction is found at 12 % of Zr while no trace of real FM is observed at 7 at % Zr. The driving force of this surprising magnetic character is the atomic volume: The lower the Zr content, the higher is the fraction of Fe atoms with compressed atomic volume having low magnetic moment. The percolation of their network separates the clusters from the FM bulk. The complex magnetic behavior of the Fe-rich Fe-Zr amorphous system at low temperatures can thus be interpreted with the only assumption of a cluster-size distribution and a weak coupling of the clusters to the FM matrix. The introduction of this coupling is able to explain the opposite pressure dependence of T g and T f . The threshold atomic volume in the low magnetic moment regions is found to be comparable to the atomic volume characteristic to the low-spin limit of the face-centered-cubic Fe alloys. The extensive literature results on the anomalous magnetism for various Fe-rich Fe-TM amorphous alloys and especially for the Fe-rich Fe-Zr glassy system are also found to be in agreement with this granular magnetic behavior.

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Magnetic behavior of cosputtered Fe-Zr amorphous thin films exhibiting perpendicular magnetic anisotropy

2008

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Cited by 3 publications

References 17 publications

Study of the magnetic viscosity of amorphous Fe - Zr alloys in the spin-glass state

Study of the magnetic viscosity of amorphous Fe - Zr alloys in the spin-glass state

Influence of the critical Fe atomic volume on the magnetism of Fe-rich metallic glasses evidenced by pressure-dependent measurements

Magnetic behavior of cosputtered Fe-Zr amorphous thin films exhibiting perpendicular magnetic anisotropy

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