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Article Dans Une Revue Journal of Physics D: Applied Physics Année : 2021

Coercivity analysis of cubic and tetragonal (Cu,Co) ferrite particles within the global model

Résumé

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.
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Dates et versions

hal-04158322 , version 1 (11-07-2023)

Identifiants

Citer

Hawa Latiff, Gabriel Gomez Eslava, Thibaut Devillers, Hideto Yanagihara, Nora Dempsey, et al.. Coercivity analysis of cubic and tetragonal (Cu,Co) ferrite particles within the global model. Journal of Physics D: Applied Physics, 2021, 54 (22), pp.224001. ⟨10.1088/1361-6463/abe5e1⟩. ⟨hal-04158322⟩

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