Magnetisation depth profiles in trilayer systems with mixed–spin interfaces—a contribution to temperature dependent GMR-potentials

Wiatrowski, G.; Baldomir, D.; Warda, K.; Pereiro, Manuel; Wojtczak, L.; Arias, J.E.

doi:10.1016/j.jmmm.2003.11.009

Cited by 10 publications

(4 citation statements)

References 35 publications

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“…The last measurements reported in [40] and extensive comparative studies of the growth, structure, magnetization and magnetotransport in Fe/Cr superlattices show that the intrinsic GMR originates from interfacial scattering and is determined by the interface width [31]. This experimental fact confirms the results shown in figure 7 and our earlier conclusion that the interface should be treated physically not as an ideal plane but as a transition zone between different materials where we can observe a mixture of two compounds (interdiffusion) and where not only a significant change of the potential but also a different kind of magnetism take place [6]. The DFT results [41] discussed in section 3.1 confirm the important role of the interface, specially the significant increase of magnetic moment at the interface for n = 5, 7 (see figure 4).…”

Section: Gmr Predictionssupporting

confidence: 88%

“…The numerical results of our calculations along with the layer potentials calculated according to equation ( 2) and the relaxation times provided by equation ( 6) are presented in tables 1 and 2. 6 According to figure 4, the behaviour of the magnetic moment versus the Fe film thickness for the interface Fe layer is non-monotonic in contrast with the surface Fe magnetic moment which ranges monotonically from 2.45 μ B for n = 1 up to 2.98 μ B for n = 8 (see fourth column of tables 1 and 2 for Fe(1) ML). We have also found the existence of highly localized states at the Fe/Cr interface when the Fe film thickness is not too small (n 4).…”

Section: Layer Magnetic Moments and Potentialsmentioning

confidence: 96%

“…Nowadays, it is well known that the interface between layers plays a dominant role in the GMR and obviously it depends strongly on the materials of the sample [6]. However, the controversy about whether GMR originates from bulk or interface scattering is still open [7].…”

Section: Introductionmentioning

confidence: 99%

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Calculations of giant magnetoresistance in Fe/Cr trilayers using layer potentials determined fromab initiomethods

Pereiro¹,

Baldomir²,

Man’kovsky³

et al. 2007

J. Phys.: Condens. Matter

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The ab initio full-potential linearized augmented plane-wave method explicitly designed for the slab geometry was employed to elucidate the physical origin of the layer potentials for the trilayers nFe/3Cr/nFe(001), where n is the number of Fe monolayers. The thickness of the transition-metal ferromagnet has been ranged from n = 1 up to n = 8 while the spacer thickness was fixed to 3 monolayers. The calculated potentials were inserted in the Fuchs-Sondheimer formalism in order to calculate the giant magnetoresistance (GMR) ratio. The predicted GMR ratio was compared with the experiment and the oscillatory behavior of the GMR as a function of the ferromagnetic layer thickness was discussed in the context of the layer potentials. The reported results confirm that the interface monolayers play a dominant role in the intrinsic GMR.

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Section: Gmr Predictionssupporting

confidence: 88%

Section: Layer Magnetic Moments and Potentialsmentioning

confidence: 96%

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Calculations of giant magnetoresistance in Fe/Cr trilayers using layer potentials determined fromab initiomethods

Pereiro¹,

Baldomir²,

Man’kovsky³

et al. 2007

J. Phys.: Condens. Matter

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“…Thus, for the case with spin-1/2 and spin-1 we can list some of the works as follows: an Ising superlattice, consisting of two ferromagnetic materials A and B, with L a layers of diluted spins S a = 1/2 and L b layers of diluted spins S b = 1 in an applied transverse field with antiferromagnetic interface coupling, was examined using the effective field theory (EFT) with a probability distribution [21]. Two works including the effects of the crystal field are: a trilayer system, with two mixed spin interfaces (S A = 1/2, S B = 1) for arbitrary concentration and varied partial film thickness, was investigated using the EFT [22]; and a ferromagnetic multilayer system, consisting of L layers of spin-1/2 Aatoms, L layers of spin-1 B-atoms and a disordered phase in between them characterized by a random arrangement of A-and B-atoms of A p B 1− p type and negative A-B coupling, were studied within the framework of the EFT [23].…”

Section: Introductionmentioning

confidence: 99%

The spin-1 and spin-3/2 model on a bilayer Bethe lattice with crystal field

Albayrak¹,

Yılmaz²

2007

J. Phys.: Condens. Matter

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A bilayer Ising model consisting of two Bethe lattices, each of which is coupled with crystal fields of different strengths and each with a branching ratio of q Ising spins with one of the layers having only spin-1 and the other having only spin-3/2, is laid over the top of the other and the two layers are tied together via an interaction between the vertically aligned spins. After obtaining the ground-state (GS) phase diagrams on different possible planes depending on the given system parameters, the changes in the order-parameters and the free energy are investigated by use of the exact recursion relations in a pairwise approach to calculate the phase diagrams of the model. The ferromagnetic ordering in each of the layers and ferromagnetic or antiferromagnetic ordering of the adjacent nearest-neighbor (NN) spins of the layers are considered. The system presents both second- and first-order phase transitions. The lines of the first-order phase transitions end on either the stable or unstable tricritical points or at the isolated critical points. The model also displays one or two compensation temperatures when the bilinear interaction of the upper layer with spin-1 can compete with that of the lower layers with spin-3/2.

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An extended Boltzmann formalism for transport description in thin Fe–Cr–Fe trilayers

Warda

Wojtczak

Baldomir

et al. 2006

Phys. Status Solidi (c)

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We present the calculations of Giant Magnetoresistance (GMR) for thin trilayers of the type nFe/3Cr/nFe where 1 ≤ n ≤ 8 for the slab geometry. All parameters used for the calculations in Boltzmann approach like the potentials, relaxation times, effective masses and the Fermi energy are determined for the different spin polarisations from electronic structure of trilayer on the base of ab initio method. The value of the parameter P corresponds to the specularity factor in Fuchs-Sondheimer theory. It is responsible for scattering electron from the metallic surface determined in analytical way. The results show a strong dependence of GMR on the ferromagnetic layer thickness as well as on the concentration of scattering centers.Inspite of the fact that from the time of the discovery of giant magnetoresistance (GMR) effects in Fe/Cr/Fe multilayers [1, 2] almost 20 years have passed and many experimental and theoretical investigations have been conducted the description of the phenomenon is not completed and it still constitutes a challenge. We should remember that studies of transport properties in metallic superlattices are affected by many inherent complexities of the material. Many possible complications arise in these types of artificial material, among them, interfacial interdiffusion at various lateral length scales [3][4][5], bulk defects, structural changes of an individual layer and overall thicknesses. The last measurements reported [6] and extensively studied of the growth, structure, magnetization and magnetotransport in Fe/Cr/Fe superlattices show that the intrinsic GMR originates mainly from interfacial scattering and is determined by the interface width. This experimental fact confirms our earlier conclusion that the interface should be treated physically not as an ideal plane but as a transition zone between different materials where we can observe a mixture of two components close to the interface especially the significant increase of magnetic moment at interface for different spin orientation [7]. In semiclassical approach the contribution of surface scattering to thin films resistance is represented by the factor P σ belonging to the interval (0,1) in the Fuchs-Sondheimer theory [8]. In the present paper, the bulk scattering is taken into account by introducing spin-dependent (spinindependent) relaxation times in the ferromagnetic (nonmagnetic) layers. In semiclassical models, the number of free parameters becomes so large that they cannot be really used for the quantitative interpretation. The parameters like relaxation times, effective masses and the values representing the heigth of

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Magnetisation depth profiles in trilayer systems with mixed–spin interfaces—a contribution to temperature dependent GMR-potentials

Cited by 10 publications

References 35 publications

Calculations of giant magnetoresistance in Fe/Cr trilayers using layer potentials determined fromab initiomethods

Calculations of giant magnetoresistance in Fe/Cr trilayers using layer potentials determined fromab initiomethods

The spin-1 and spin-3/2 model on a bilayer Bethe lattice with crystal field

An extended Boltzmann formalism for transport description in thin Fe–Cr–Fe trilayers

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