On the orientational dependence of giant magnetoresistance

Blaas, C.; Weinberger, P.; Szunyogh, L.; Kudrnovský, J.; Drchal, V.; Levy, Peter M.; Sommers, C.

doi:10.1007/s100510050763

Cited by 16 publications

(19 citation statements)

References 13 publications

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“…From the experimental side, the angular variation of the GMR was found to be very close to the relation GMR(ϕ) ∝ (1 -cos ϕ) in the CIP geometry for various systems: Fe/Cr/Fe (Ref. 51 This way, for a given magnetic field H if we know the equilibrium angle φ(H) between the two magnetic vectors, from this we can get the GMR value for any φ(H), thus we can determine 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.…”

Section: Calculation Of the Gmr(h) Curvessupporting

confidence: 56%

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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

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─ 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.

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Section: Calculation Of the Gmr(h) Curvessupporting

confidence: 56%

“…It can be observed in Fig. 3b that the GMR(H) curve changes only slightly if, in addition to the (1 -cos ϕ) term, also the quadratic term (1 -cos 2 ϕ) as calculated by Blaas et al 51 is taken into account for describing the angular dependence of the GMR.…”

Section: Fig 2 Dependence Of the Equilibrium Angle ϕ Between The Twomentioning

confidence: 82%

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

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“…where θ is the angle between the magnetization of the two layers and ∆R = R AP − R P . Different approaches to a theoretical analysis of the angular dependence predict that the conductance, not the resistance, varies as cos θ [112][113][114]. Although the deviations of the resistance from the cos θ dependence is second order in the GMR ratio they are noticeable in the data shown in Fig.…”

Section: Giant Magnetoresistancementioning

confidence: 94%

Electrical detection of magnetization dynamics via spin rectification effects

2016

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The purpose of this article is to review the current status of a frontier in dynamic spintronics and contemporary magnetism, in which much progress has been made in the past decade, based on the creation of a variety of micro-and nano-structured devices that enable electrical detection of magnetization dynamics. The primary focus is on the physics of spin rectification effects, which are well suited for studying magnetization dynamics and spin transport in a variety of magnetic materials and spintronic devices. Intended to be intelligible to a broad audience, the paper begins with a pedagogical introduction, comparing the methods of electrical detection of charge and spin dynamics in semiconductors and magnetic materials respectively. After that it provides a comprehensive account of the theoretical study of both the angular dependence and line shape of electrically detected ferromagnetic resonance (FMR), which is summarized in a handbook formate easy to be used for analyzing experimental data. We then review and examine the similarity and differences of various spin rectification effects found in ferromagnetic films, magnetic bilayers and magnetic tunnel junctions, including a discussion of how to properly distinguish spin rectification from the spin pumping/inverse spin Hall effect generated voltage. After this we review the broad applications of rectification effects for studying spin waves, nonlinear dynamics, domain wall dynamics, spin current, and microwave imaging. We also discuss spin rectification in ferromagnetic semiconductors. The paper concludes with both historical and future perspectives, by summarizing and comparing three generations of FMR spectroscopy which have been developed for studying magnetization dynamics.

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“…The GMR effect originally discovered in FM/NM multilayer structures [1,2] is the highest when the adjacent layer magnetizations are antiparallel aligned [6][7][8]. In physically deposited multilayer structures, this can be achieved by choosing spacer layer thicknesses ensuring an AF coupling between adjacent layers which occurs at the so-called AF maxima [9][10][11].…”

Section: Introductionmentioning

confidence: 99%

Magnetic and magnetoresistance studies of nanometric electrodeposited Co films and Co/Cu layered structures: Influence of magnetic layer thickness

Zsurzsa

Péter

Kiss

et al. 2017

Journal of Magnetism and Magnetic Materials

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-The magnetic properties and the magnetoresistance behavior were investigated for electrodeposited nanoscale Co films, Co/Cu/Co sandwiches and Co/Cu multilayers with individual Co layer thicknesses ranging from 1 nm to 20 nm. The measured saturation magnetization values supported reasonably the validity of the nominal layer thicknesses. All three types of layered structure exhibited anisotropic magnetoresistance for thick magnetic layers whereas the Co/Cu/Co sandwiches and Co/Cu multilayers with thinner magnetic layers exhibited giant magnetoresistance (GMR), the GMR magnitude being the largest for the thinnest Co layers. The decreasing values of the relative remanence and the coercive field when reducing the Co layer thickness down to below about 3 nm indicated the presence of superparamagnetic (SPM) regions in the magnetic layers which could be more firmly evidenced for these samples by a decomposition of the magnetoresistance vs. field curves into a ferromagnetic and an SPM contribution. For thicker magnetic layers, the dependence of the coercivity (H c ) on magnetic layer thickness (d) could be described for each of the layered structure types by the usual equation H c = H co + a/d n with an exponent around n = 1. The common value of n suggests a similar mechanism for the magnetization reversal by domain wall motion in all three structure types and hints, at the same time, for the absence of coupling between magnetic layers in the Co/Cu/Co sandwiches and Co/Cu multilayers.

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On the orientational dependence of giant magnetoresistance

Cited by 16 publications

References 13 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

Electrical detection of magnetization dynamics via spin rectification effects

Magnetic and magnetoresistance studies of nanometric electrodeposited Co films and Co/Cu layered structures: Influence of magnetic layer thickness

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