Magnetic vector model of spin-valves

Parker, M.R.; Fujiwara, Hideo; Hossain, S.; Webb, William

doi:10.1109/20.490071

Cited by 15 publications

(7 citation statements)

References 4 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Some of our results could be compared with earlier works, [21][22][23][24][25][26][27][28][29][30][31][32][33] and these agree very well. For more complex combinations, the limiting cases yielded the results derived previously for simpler cases.…”

Section: Discussionsupporting

confidence: 87%

“…Subsequently, Fujiwara and Parker 22 presented an analytical model for finite number of layers in case of bilinear and biquadratic exchange with uniaxial anisotropy which model was solved for some specific values of the coupling constants and the anisotropy constant only. Several further reports have been published 23,24,26,27,32 which rely on this model.…”

Section: Introductionmentioning

confidence: 95%

See 1 more Smart Citation

Modeling the Magnetoresistance versus Field Curves of GMR Multilayers with Antiferromagnetic and/or Orthogonal Coupling by Assuming Single-Domain State and Coherent Rotations

Szász¹,

Bakonyi²

2012

J Spintron Magnet Nanomat

View full text Add to dashboard Cite

─ In order to better understand the role of possible couplings in determining the giant magnetoresistance (GMR) behavior of multilayers, a knowledge of the dependence of the GMR on magnetic field H appears to be useful. Since a few specific cases have only been treated theoretically in the literature, it was decided to carry out a modeling of the GMR(H) curves of ferromagnetic/non-magnetic (FM/NM) multilayers with various interlayer couplings. For simplicity, we focused on a trilayer structure (FM 1 /NM/FM 2 ) corresponding fairly well to the case of a large number of FM/NM bilayers. To carry out the calculations, some fundamental assumptions were made: (i) each FM layer consists of a single domain and the magnetizations are in the layer planes; (ii) the magnetization of each layer is the same; (iii) the magnetization vectors rotate in the plane of the layers in an external magnetic field. In order to calculate the GMR(H) function, we need to know the magnetization process in the trilayer, i.e., the M(H) function. Therefore, first we calculate the equilibrium angle ϕ(H) between the two magnetization vectors as a function of the field by minimizing the total energy of the multilayer. According to most previous theoretical and experimental works, the angular dependence of the GMR is fairly well described by the relation GMR(ϕ) ∝ (1 -cos ϕ) and we used this relation to derive the GMR(H) function. Along this line, the M(H) and GMR(H) curves were calculated for the following cases: (i) pure AF coupling; (ii) pure orthogonal coupling; (iii) AF coupling and orthogonal coupling simultaneously present. As to the calculation of the GMR(H) curves, some of these configurations have not yet been treated formerly or for some specific parameter values only. For those cases for which calculations were reported in the literature for M(H) and GMR(H), our results agree with previous reports.

show abstract

Section: Discussionsupporting

confidence: 87%

Section: Introductionmentioning

confidence: 95%

Modeling the Magnetoresistance versus Field Curves of GMR Multilayers with Antiferromagnetic and/or Orthogonal Coupling by Assuming Single-Domain State and Coherent Rotations

Szász¹,

Bakonyi²

2012

J Spintron Magnet Nanomat

View full text Add to dashboard Cite

show abstract

“…1 is the variation of ⌬R/R at zero applied field, where, in the hard direction curve, the value of ⌬R/R is higher at zero field than at high field. We attribute this behavior, which has been described and quantified in detail previously, 7,8 to anisotropic magnetoresistance ͑AMR͒ rather than to the possible existence of high resistivity regions of the spin valve with oppositely directed pinned and free films at zero field. Note that in Fig.…”

Section: A As-deposited Mr Curvesmentioning

confidence: 54%

Thermal stability of Ta-pinned spin valves

Fry

McMichael

Bonevich

et al. 2001

Journal of Applied Physics

View full text Add to dashboard Cite

It has recently been found that large uniaxial anisotropy fields in excess of 120 kA/m ͑1500 Oe͒ can be created in thin ͑3-5 nm͒ films of Co by obliquely sputtered Ta underlayers. This anisotropy can be used to pin the bottom film of a spin valve while having only a modest effect on the top ''free'' film, separated by a 2.5 nm Cu spacer layer. This article describes measurements of thermal stability in these Ta-pinned spin valves. Using room temperature giant magnetoresistance ͑GMR͒ as a measure, we find that the structure is stable under cumulative 20 min anneals at 25°C intervals up to 300°C; GMR decreases to zero upon further anneals up to 450°C. Measurements taken at elevated temperatures reveal that GMR decreases linearly with temperature, extrapolating to zero at approximately 425°C, while the anisotropy field is much less temperature dependent, remaining nearly constant up to 150°C and gradually decreasing to 50% of its room temperature value at 325°C.

show abstract

“…In an unpatterned spin-valve structure the switching field interval depends on the interplay, between the induced in-plane anisotropy of the magnetic layers, the interlayer coupling, and the exchange-biasing of the pinned magnetic layer. Model treatments of this interplay have been given by Rijks et al 9 ͑neglecting the induced anisotropy of the sensitive and pinned magnetic layers͒ and by Parker et al 10 However, so far no systematic experimental study of the switching field interval in exchange-biased spin valves has been carried out.…”

Section: Introductionmentioning

confidence: 99%

Switching field interval of the sensitive magnetic layer in exchange-biased spin valves

Rijks

Reneerkens²,

Coehoorn

et al. 1997

Journal of Applied Physics

View full text Add to dashboard Cite

The switching field interval, ⌬H s , of Ni-Fe-Co-based thin films and spin-valve layered structures, sputter-deposited on a Ta-buffer layer, was studied. The switching field interval is the field range in which the magnetization reversal of a ferromagnetic layer takes place. In thin films, ⌬H s is determined by the uniaxial anisotropy, induced by growth in a magnetic field. This anisotropy increases with the ferromagnetic layer thickness and saturates at a thickness of 10-25 nm. It also depends on the alloy composition as well as on the choice of the adjacent layers. In exchange-biased spin valves, an additional contribution to ⌬H s was observed, which increases monotonically with increasing interlayer coupling. We explain this in terms of the effect on the magnetization reversal of the sensitive layer due to a simultaneous small, but temporary, magnetization rotation in the exchange-biased layer and lateral variations of the interlayer coupling. In addition, the effect of biquadratic coupling on ⌬H s is discussed. Finally, the thermal stability of ⌬H s is investigated.

show abstract

Magnetic vector model of spin-valves

Cited by 15 publications

References 4 publications

Modeling the Magnetoresistance versus Field Curves of GMR Multilayers with Antiferromagnetic and/or Orthogonal Coupling by Assuming Single-Domain State and Coherent Rotations

Modeling the Magnetoresistance versus Field Curves of GMR Multilayers with Antiferromagnetic and/or Orthogonal Coupling by Assuming Single-Domain State and Coherent Rotations

Thermal stability of Ta-pinned spin valves

Switching field interval of the sensitive magnetic layer in exchange-biased spin valves

Contact Info

Product

Resources

About