Investigation of anisotropy by ferromagnetic resonance (FMR) in exchange-coupled bilayer films

Layadi, A.; Cain, William; Lee, J.-W.; Artman, J. O.

doi:10.1109/tmag.1987.1065502

Cited by 49 publications

(24 citation statements)

References 6 publications

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“…On the other hand, the H r curve for the thick Cu spacer inserted films exhibit similar behavior to the NiFe single layer thin film, corresponding to weak and long-range exchange coupling through Cu spacer layer. An unidirectional anisotropy field ðH ex Þ and an uniaxial anisotropy field ðH k Þ can be extracted by the phenomenological expression [5] of cosine series neglecting high-order term as follows:…”

Section: Resultsmentioning

confidence: 99%

Influence of spacer layer in exchange coupled NiFe/Cu/IrMn trilayer structure

Yoo¹,

Min²,

Yu³

2006

Journal of Magnetism and Magnetic Materials

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Section: Resultsmentioning

confidence: 99%

Influence of spacer layer in exchange coupled NiFe/Cu/IrMn trilayer structure

Yoo¹,

Min²,

Yu³

2006

Journal of Magnetism and Magnetic Materials

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“…Our values also agree with those obtained in other works on this system. 3,14,17 It can be seen that the two sets of estimated anisotropy parameters are quite different. The comparison between the effective fields ͑Table I͒ used in the fit of the angular variations in Fig.…”

Section: 10mentioning

confidence: 99%

“…One notes that there is an asymmetry in the initial part of this plot; a very similar curve has been observed in the H res angular variation for a NiFe/␣-Fe 2 O 3 exchange-bias bilayer. 14 There, the authors assigned this asymmetry to hysteresis memory, i.e., training effects, due to successive changes of the uncompensated interfacial AF magnetizations. We also believe that the effect observed here is a related phenomenon.…”

Section: 10mentioning

confidence: 99%

Frequency-dependent exchange bias in NiFe/NiO films

et al. 2003

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Ferromagnetic ͑FM͒ resonance and magnetization curve measurements were performed at room temperature for a polycrystalline Ni 81 Fe 19 coupled to NiO. It was observed that the shape of the angular variation of the resonance field is frequency dependent, with the curve at 9.65 GHz typical for a strongly exchange-coupled bilayer, while the 34.0 GHz curve is characteristic for relatively weak interactions. Numerical simulations of the resonance field and of the hysteresis loop shift, carried out through the domain wall formation model, as well as the resonance linewidth data indicated that there must be two fractions in the antiferromagnetic part of the interface, with stable and unstable grains. Only the stable grains contribute to the exchange bias. In our sample, whether an interfacial antiferromagnetic grain is stable or not is predominantly determined by the strength of the exhange coupling between this grain and the adjacent FM domain. The stable antiferromagnetic grains, whose contribution is sensed by the resonance experiment, are the smaller ones, which are more strongly coupled to the ferromagnet than the larger grains. The exchange-bias phenomenon, 1 which results from the interfacial coupling between ferromagnetic ͑FM͒ and antiferromagnetic ͑AF͒ materials, has been extensively studied in the last decade, motivated by fundamental and practical interests. One of the reasons for the continued interest is the fact that different experimental techniques may yield different exchange anisotropy values. [2][3][4][5][6][7][8][9] In some cases, this was assigned to the fact that the measurements are performed on different sets of samples. 4 Another source for the discrepancy could be the reliability of the model used in the experimental data interpretation. 8 It has also been shown 9 that the exchange-bias field values derived from magnetization and ferromagnetic resonance ͑FMR͒ measurements, must, in general, give different values in the framework of the domain-wall formation ͑DWF͒ model which assumes formation of a planar domain wall at the AF side of the interface with the reversal of the FM orientation. 8,10 Recent FMR studies on exchange-coupled NiFe films showed the importance of the magnetic state of the AF part of the interface. McMichael et al.11 used FMR to study the relaxation behavior of polycrystalline AF layer and found that the stability of the AF order is critical to the existence of the exchange bias. Relaxation related to thermally driven reversal of the AF grains in such systems has also been observed. 12,13The aim of the present work was to apply the phenomenological approach for the DWF model recently developed by our group 9 on a real exchange coupled system. The paper describes FMR and magnetization measurements of a bilayer of Permalloy ͑Py͒ ͑here, Ni 81 Fe 19 ) exchange-coupled to NiO. The striking frequency dependence of the FMR angular variation has been related to the relaxation behavior of the interfacial AF grains.The sample under investigation was deposited by rf magnetron sputterin...

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“…If exchange bias field is parallel to EA of the F-layer form the angle θ with the direction of the external field, then for 4πM s >> H r field H r is determined by the intrinsic resonance field H r0 = (Z/J) 2 /(4πM s ) of the Flayer and values of H K and H EB and angle θ, according to the expression [9,10]:…”

Section: Samples Preparation and Measuringmentioning

confidence: 99%

Influence of surface roughness and deposition order on exchange bias in bilayer structures NiFe/IrMn

Shanova

Dzhun

Чеченин

2014

EPJ Web of Conferences

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Using ferromagnetic resonance (FMR) method, magnetic properties of bilayer structures consisting of ferromagnetic (F, Ni 80 Fe 20 ) and antiferromagnetic (AF, Ir 25 Mn 75 ) layers with alternative order of F and AF deposition were studied. It was found that the surface roughness is larger for the samples with AF on the top of F layers. The influence of AF layer thickness on the surface roughness and exchange bias for different types of structures was discussed.

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Investigation of anisotropy by ferromagnetic resonance (FMR) in exchange-coupled bilayer films

Cited by 49 publications

References 6 publications

Influence of spacer layer in exchange coupled NiFe/Cu/IrMn trilayer structure

Influence of spacer layer in exchange coupled NiFe/Cu/IrMn trilayer structure

Frequency-dependent exchange bias in NiFe/NiO films

Influence of surface roughness and deposition order on exchange bias in bilayer structures NiFe/IrMn

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