GMR effect across the transition from multilayer to granular structure

Spizzo, F.; Angeli, E.; Bisero, D.; Vavassori, P.; Ronconi, F.

doi:10.1016/s0304-8853(01)01064-2

Cited by 13 publications

(15 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The typical SPM moments obtained previously on electrodeposited Co/Cu multilayers [32][33][34][35][36] Previous reports by other researchers on both electrodeposited [36,37] and sputtered [38][39][40] Co/Cu multilayers with very thin Co layers around 1 nm and below gave further support to our findings and conclusions concerning the appearance of SPM regions in such multilayers. Namely, it turned out from these studies when increasing the Co layer thickness in the subnanometer range that whereas the M(H) curves evolve from a hysteresis-less behavior to the appearance of a clear hysteresis, i.e., the formation of FM regions, the MR(H) curves remain still strongly non-saturating with negligible hysteresis.…”

Section: Co/cu Multilayerssupporting

confidence: 91%

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

View full text Add to dashboard Cite

-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.

show abstract

Section: Co/cu Multilayerssupporting

confidence: 91%

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

View full text Add to dashboard Cite

show abstract

“…Magnetic measurements have often revealed 7,12,15,17,18,21,23,29,30 that in multilayers, in addition to the ferromagnetic (FM) term, the magnetization also has a superparamagnetic (SPM) term, the latter one sometimes even dominating over the FM contribution. The phenomenon of nonsaturating magnetoresistance and the occurrence of a SPM magnetization contribution are not restricted to any specific deposition technique or element combination since, depending on layer thicknesses and specific deposition conditions, it has been observed in multilayers of the Co/ Au, Co/ Cu, Ni/ Cu, Ni-Fe/ Cu, and Ni-Co/ Cu systems grown by various methods such as molecular-beam epitaxy (MBE), sputtering, or electrodeposition.…”

Section: Introductionmentioning

confidence: 99%

Decomposition of the magnetoresistance of multilayers into ferromagnetic and superparamagnetic contributions

et al. 2004

View full text Add to dashboard Cite

An analysis of both magnetic and magnetotransport properties is presented for electrodeposited multilayers prepared intentionally under conditions to make the superparamagnetic (SPM) magnetization contribution comparable to or larger than the ferromagnetic term. Based on a model elaborated for the giant magnetoresistance (GMR) of granular metals [N. Wiser, J. Magn. Magn. Mater. 159, 119 (1996); B. Hickey et al., Phys. Rev. B. 51, 667 (1995)], it is shown that in such multilayers both the magnetization and the GMR can be decomposed into ferromagnetric and superparamagnetic contributions where the latter term is described by a Langevin function. The size of the SPM regions estimated from the experimental data is in the nanoscale regime. It is believed that the method applied here gives a quantitative answer to the problem of the often observed nonsaturating behavior of GMR in multilayers. Electrodeposited multilayers are particularly prone to this feature although the occurrence of SPM regions is quite common in multilayers prepared by any technique. Therefore, this type of analysis should help better understanding of the factors influencing the GMR of multilayer films.

show abstract

“…Згідно [35], в спін-клапанній структурі (Ni-Fe)/Au/Co/Au величина ГМО зале-жить від товщини шару Со і досягає максимального значення при d Co ≈ 0,5-0,6 нм, в той час як у ґранульованому стопі при с ≈ 25-35 ат.% Со, що якісно узгоджується з [7]. Ряд авторів (див., напри-клад, [36]) спостерігали зменшення величини ГМО при збільшенні температури відпалювання, що спричиняє збільшення середнього розміру ґрануль Со. Важливо підкреслити, що в роботі [36] плівкові ГС одержувалися не шляхом одночасної конденсації компонент, а при зменшенні товщини шарів Cu і Co або в процесі високотемпера-турного відпалювання.…”

Section: плівкові системи в яких стабілізуються тверді розчиниunclassified

“…Ряд авторів (див., напри-клад, [36]) спостерігали зменшення величини ГМО при збільшенні температури відпалювання, що спричиняє збільшення середнього розміру ґрануль Со. Важливо підкреслити, що в роботі [36] плівкові ГС одержувалися не шляхом одночасної конденсації компонент, а при зменшенні товщини шарів Cu і Co або в процесі високотемпера-турного відпалювання. Відмітимо, що у всіх наших дослідженнях [10,12,16,17,23,25,29] ми застосовували метод послідовної кон-денсації шарів з наступною, як і в [36], термообробкою.…”

Section: плівкові системи в яких стабілізуються тверді розчиниunclassified

“…Важливо підкреслити, що в роботі [36] плівкові ГС одержувалися не шляхом одночасної конденсації компонент, а при зменшенні товщини шарів Cu і Co або в процесі високотемпера-турного відпалювання. Відмітимо, що у всіх наших дослідженнях [10,12,16,17,23,25,29] ми застосовували метод послідовної кон-денсації шарів з наступною, як і в [36], термообробкою. Таким ме-тодом ми одержували ґранульовані, -(Cu, Co), (Ag, Co) та (Au, Co), -або неґранульовані, -(α-Fe, Cr), -тверді розчини.…”

Section: плівкові системи в яких стабілізуються тверді розчиниunclassified

See 1 more Smart Citation

Structural-Phase State, Stability of Interfaces and Electrophysical Properties of Two-Layer Film Systems

et al. 2007

View full text Add to dashboard Cite

GMR effect across the transition from multilayer to granular structure

Cited by 13 publications

References 11 publications

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

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

Decomposition of the magnetoresistance of multilayers into ferromagnetic and superparamagnetic contributions

Structural-Phase State, Stability of Interfaces and Electrophysical Properties of Two-Layer Film Systems

Contact Info

Product

Resources

About