Asymmetric magnetization reversal on exchange biased CoO/Co bilayers

Radu, F.; Etzkorn, Markus; Schmitte, T.; Siebrecht, R.; Schreyer, A.; Westerholt, K.; Zabel, H.

doi:10.1016/s0304-8853(01)00815-0

Cited by 78 publications

(66 citation statements)

References 13 publications

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“…In accordance with recent results on CoO/Co, 27 the training effect originates mainly from the cycle-dependent shift for H C 1 while H C 2 remains virtually constant. The training effect is accompanied by a cycle-dependent decrease of the total satu- FIG.…”

Section: ͑4͒supporting

confidence: 92%

“…A similar behavior was found on CoO/Co bilayers where coherent rotation has been observed at H C 2 while domain nucleation and wall propagation dominates in the vicinity of H C 1 . [25][26][27] Moreover, in this case it was found that the first magnetization reversal in the virgin state is exceptional in the sense that pure 180°domain-wall movement takes place at H C 1 . In accordance with these findings we observe in our NiO/Fe heterostructure an exceptional large training effect between the first and the second hysteresis loop.…”

Section: Training Of the Exchange-bias Effect In Nio-fe Heterostructuresmentioning

confidence: 69%

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Training of the exchange-bias effect in NiO-Fe heterostructures

Hochstrat¹,

Binek²,

Kleemann³

2002

Phys. Rev. B

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Section: ͑4͒supporting

confidence: 92%

Section: Training Of the Exchange-bias Effect In Nio-fe Heterostructuresmentioning

confidence: 69%

Training of the exchange-bias effect in NiO-Fe heterostructures

Hochstrat¹,

Binek²,

Kleemann³

2002

Phys. Rev. B

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“…It is conceivable to think that this behaviour originates from sudden consecutive breaking of domain walls and consequent jumps from a pinning magnetic defect to the next one, whereas the smoother SFD observed when the magnetization switches back to the initial more stable orientation is related to a coherent rotation of the magnetic moments. This conjecture is consistent with similar conclusions derived from polarized neutron reflectivity, anisotropic magneto resistance and Kerr microscopy on CoO/Co bilayers [8,9].…”

Section: Joint European Magnetic Symposia 2012supporting

confidence: 92%

Influence of Cu seed layer on the magnetization reversal in exchange-biased FeMn/FeCo systems

Cavicchia

D’Orazio

Rossi

et al. 2013

EPJ Web of Conferences

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Abstract. Magnetization hysteresis loops are measured on FeMn/FeCo bilayers. The existence of the exchange bias effect up to room temperature is guaranteed by the presence of copper as a seed layer. We demonstrate that the choice of the growth parameters for Cu allows the control of the magnetic response of the structure, tuning the coercivity and the exchange field. The switching field distribution suggests different magnetization reversal mechanisms during the ascending and descending branches of the hysteresis loop. The evident noisy character of the data, during the reversal of the magnetization with respect to the initially set orientation, supports the picture of domain wall motion involving pinned states at magnetic defects, contrasting with the coherent magnetic moments rotation along the opposite branch.

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“…Due to the highly oxidative nature of the cobalt element, exposing the Co layer to ambient atmosphere leads to the formation of an antiferromagnetic polycrystalline CoO layer at the surface. [31][32][33][34][35] In this work the Co NTs were left in air for 9 months, prior to their magnetic characterization, forming an estimated oxide layer thickness of $4 nm. Temperature (6-250 K) dependent magnetic measurements were performed after field cooling the samples in 50 kOe from above room temperature, using a superconducting quantum interference device (SQUID) MPMS magnetometer from Quantum Design, and with the magnetic field (H) applied perpendicular to the NT axis.…”

Section: Methodsmentioning

confidence: 99%

“…One should note that, due to the highly oxidative nature of cobalt, an oxide layer of $2 nm is expected to be formed after a few days of exposure to ambient atmosphere. [31][32][33][34][35] Therefore, we estimate the thicknesses of the FM/AFM layers in Co/CoO NTs after 4 and 9 months of oxidation as (t FM ; t AFM ) $ (7, 3) nm and $ (6, 4) nm, respectively. Such increase in the AFM layer thickness affects the strength of the FM/AFM coupling.…”

Section: Training Effect Of Ebmentioning

confidence: 99%

Temperature dependence of the training effect in electrodeposited Co/CoO nanotubes

Proença

Ventura

Sousa

et al. 2013

Journal of Applied Physics

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High aspect ratio Co/CoO nanotubes (NTs) were obtained by potentiostatic electrodeposition of Co inside nanoporous alumina templates followed by the natural oxidation of their inner walls. Magnetic measurements performed at low temperatures after field cooling the samples from above its blocking temperature (T B $ 220 K), evidenced the existence of exchange bias (EB) coupling between the Co ferromagnetic outer wall and the CoO antiferromagnetic inner wall of the NTs. A decrease in the magnitude of the EB field was measured at T < T B when cycling the Co/CoO NT arrays through consecutive hysteresis loops. This decrease is known as the training effect (TE) and is here studied in the 6 K T < T B temperature range. The TE was fitted using the recursive Binek formula, giving small values for the characteristic decay rate of the training behavior, and evidencing a decrease of EB with increasing antiferromagnetic layer thickness. A phenomenological theory for the temperature dependence of the TE in exchange biased systems was applied for the first time to core-shell nanotubular structures. The good agreement obtained between the experimental results and the theoretical data, provided a strong confirmation of the qualitative correctness of the spin configuration relaxation model used in these systems.

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Asymmetric magnetization reversal on exchange biased CoO/Co bilayers

Cited by 78 publications

References 13 publications

Training of the exchange-bias effect in NiO-Fe heterostructures

Training of the exchange-bias effect in NiO-Fe heterostructures

Influence of Cu seed layer on the magnetization reversal in exchange-biased FeMn/FeCo systems

Temperature dependence of the training effect in electrodeposited Co/CoO nanotubes

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