Noncollinear Fe spin structure in (Sm-Co)/Fe exchange-spring bilayers: Layer-resolved<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msup><mml:mrow /><mml:mn>57</mml:mn></mml:msup></mml:math>Fe Mössbauer spectroscopy and electronic structure calculations

Uzdin, V. M.; Vega, A.; Khrenov, A. N.; Keune, W.; Kuncser, V.; Jiang, J. S.; Bader, S. D.

doi:10.1103/physrevb.85.024409

Cited by 33 publications

(16 citation statements)

References 35 publications

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“…The noncollinar Alexander-Anderson (NCAA) model has been found to describe well magnetism of itinerant electrons in 3d transition metals [45,46]. While the evaluation of the energy requires self-consistency calculations, analytical forces provided by a force theorem [11] make it relatively easy to navigate on the energy surface and find local minima corresponding to (meta)stable magnetic states with possibly complex, non-collinear ordering of the magnetic moments.…”

Section: Annihilation Of An Antivortexmentioning

confidence: 99%

Method for finding mechanism and activation energy of magnetic transitions, applied to skyrmion and antivortex annihilation

Bessarab

Uzdin

Jónsson

2015

Computer Physics Communications

204

250

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A method for finding minimum energy paths of transitions in magnetic systems is presented and used to determine the mechanism and estimate the activation energy of skyrmion and antivortex annihiliation in nano-systems. The path is optimized with respect to orientation of the magnetic vectors while their magnitudes are fixed or obtained from separate calculations. The curvature of the configuration space is taken into account by: (1) using geodesics to evaluate distances and displacements of the system during the optimization, and (2)

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Section: Annihilation Of An Antivortexmentioning

confidence: 99%

Method for finding mechanism and activation energy of magnetic transitions, applied to skyrmion and antivortex annihilation

Bessarab

Uzdin

Jónsson

2015

Computer Physics Communications

204

250

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“…[1][2][3][4][5][6][7][8] The proposition for exchange spring concept has been attributed to Knellers and Hawig. 9 They proposed an enhancement in content of transition metal in permanent magnets by making a nanocomposite comprising exchange-coupled hard and soft magnetic phases.…”

Section: Introductionmentioning

confidence: 99%

Exchange spring behaviour in SrFe12O19-CoFe2O4 nanocomposites

Roy

Kumar

2015

AIP Advances

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Nanocomposites of hard (SrFe12O19) and soft ferrite (CoFe2O4) are prepared by mixing individual ferrite components at appropriate weight ratio and subsequent heat treatment. The magnetization of the composites showed hysteresis loop that is characteristic of the exchange spring system. The variation of Jr/Jr(∞) vs. Jd/ Jr(∞) for these nanocomposites are investigated to understand the presence of both the interacting field and the disorder in the system. This is further corroborated with the First Order Reversal Curve analysis (FORC) on the nanocomposites of 1:4 (Cobalt Ferrite: Strontium Ferrite) and 1:16 (Cobalt Ferrite: Strontium Ferrite). The FORC distribution reveals that the pinning mechanism is stronger in the nanocomposite of 1:4 compared to 1:16. However, the nanocomposite of 1:16 exhibit superior exchange coupling strength in contrast to 1:4. The asymmetric nature of the FORC distribution at Hc = 0 Oe for both the nanocomposites validates the intercoupling between the reversible and irreversible magnetization.

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“…One such active field of research is the exchange spring magnet [3][4][5][6][7] , where high saturation magnetization of the soft and the high magnetic anisotropy of the hard magnetic phases are exchange coupled in the nanometric scale. Both the experimental studies and the Micromagnetic calculations [8][9][10][11] reveal that significant improvements in terms of magnetic energy product (BH) max can be achieved using the exchange spring magnet.…”

Section: Introductionmentioning

confidence: 99%

Investigation on non-exchange spring behaviour and exchange spring behaviour: A first order reversal curve analysis

Roy¹,

Sreenivasulu²,

Kumar³

2013

Applied Physics Letters

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The magnetization behaviour of the soft Cobalt Ferrite-hard Strontium Ferrite nanocomposite is tuned from the non exchange spring nature to the exchange spring nature, by controlling the particle size of the soft Cobalt Ferrite in the Cobalt Ferrite: Strontium Ferrite (1:8) nanocomposite. The relative strength of the interaction governing the magnetization process in the nanocomposites is investigated using Henkel plot and First Order Reversal Curve (FORC) method. The FORC method has been utilized to understand the magnetization reversal behaviour as well as the extent of the irreversible magnetization present in both the nanocomposites having smaller and larger particle size of the Cobalt Ferrite. The magnetization process is primarily controlled by the domain wall movement in the nanocomposites. Using the FORC distribution in the (H a , H b ) co-ordinate, the onset of the nucleation field, invasion of the domain wall from the soft to the hard phase, domain wall annihilation and the presence of the reversible magnetization with the applied reversal field for both the nanocomposites has been investigated. It has been found that for the composite having lower particle size of the soft phase shows a single switching behaviour corresponding to the coherent reversal of the both soft and hard phases. However, the composite having higher Cobalt Ferrite particle size shows two peak behaviour in the FORC distribution resembling individual switching of the soft and hard phases. The FORC distribution in (H u , H c ) co-ordinate and the Henkel measurement confirms the dominant exchange interaction in the nanocomposites exhibiting exchange spring behaviour where as the occurrence of both the dipolar and exchange interaction is substantiated for the non exchange coupled nanocomposite. The asymmetric nature of the FORC distribution at H c = 0 Oe for both the nanocomposites validates the intercoupled nature of the reversible and irreversible magnetizations in both the nanocomposites. It is also concluded that the contribution of the reversible magnetization is more in the nanocomposite having lower particle size of the Cobalt Ferrite compared to the nanocomposite having higher particle size of the Cobalt Ferrite.

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Noncollinear Fe spin structure in (Sm-Co)/Fe exchange-spring bilayers: Layer-resolved57Fe Mössbauer spectroscopy and electronic structure calculations

Cited by 33 publications

References 35 publications

Method for finding mechanism and activation energy of magnetic transitions, applied to skyrmion and antivortex annihilation

Method for finding mechanism and activation energy of magnetic transitions, applied to skyrmion and antivortex annihilation

Exchange spring behaviour in SrFe12O19-CoFe2O4 nanocomposites

Investigation on non-exchange spring behaviour and exchange spring behaviour: A first order reversal curve analysis

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