In:
Journal of Physics D: Applied Physics, IOP Publishing, Vol. 54, No. 22 ( 2021-06-03), p. 224001-
Abstract:
We analyzed the coercivity of both cubic and tetragonally distorted Co x Cu 1− x Fe 2 O 4 particles ( x = 0.2 and 0.1, respectively) using the global model. According to magnetic viscosity measurements, the size of the activation volumes v a increases from around 2000 nm 3 ( v a 1/3 ≈ 13 nm) at 10 K for both samples, to close to 175 000 nm 3 for the cubic sample and 5400 nm 3 for the tetragonally distorted sample at 300 K. The microstructure-related phenomenological parameters obtained from the global model analysis are α = 0.29 and N eff = −0.01 and α = 0.39 and N eff = −0.24 for the cubic and tetragonal samples, respectively. High-resolution transmission electron microscopy images of the tetragonal sample showed that nanograins are connected through a thin amorphous layer (∼1 nm), which could account for the intergranular exchange interactions indicated by the negative value of N eff as well as values of M r / M s 〉 0.5 for such isotropic samples. Low temperature discrepancies are tentatively attributed to magnetic reversal being governed by a local heating process following thermal activation.
Type of Medium:
Online Resource
ISSN:
0022-3727
,
1361-6463
DOI:
10.1088/1361-6463/abe5e1
Language:
Unknown
Publisher:
IOP Publishing
Publication Date:
2021
detail.hit.zdb_id:
209221-9
detail.hit.zdb_id:
1472948-9
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