Time dependence of the magnetization process of RE-TM alloys

Labrune, M.; Andrieu, S.; Rı́o, Fernando del; Bernstein, P.

doi:10.1016/0304-8853(89)90120-0

Cited by 196 publications

(155 citation statements)

References 9 publications

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“…It is common practice to employ the Fatuzzo-Labrune theory [17,19] to interpret magnetization reversal in thin films. The theory uses two microscopic phenomena:…”

Section: Magnetization Reversal At Constant Magnetic Fieldmentioning

confidence: 99%

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Dynamics of successive minor hysteresis loops

2012

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Cumulative growth of successive minor hysteresis loops in Co/Pd multilayers with perpendicular anisotropy was studied in the context of time dependent magnetization reversal dynamics. We show that in disordered ferromagnets, where magnetization reversal involves nucleation, domains' expansion and annihilation, differences between the time dependencies of these processes are responsible for accumulation of nuclei for rapid domain expansion, for the asymmetry of forward and backward magnetization reversals and for the respective cumulative growth of hysteresis loops. Loops stop changing and become macroscopically reproducible when populations of upward and downward nucleation domains balance each other and the respective upward and downward reversal times stabilize. PACS: 75.60.Jk, 75.70.Cn, IntroductionReproducibility of cycling processes under identical external conditions attracts particular attention in studies of magnetic hysteresis for at least two reasons: the effect is fundamental to all magnetic storage technologies, and it can serve as a model for a wide range of type-I phase transitions. Two types of hysteresis loops are distinguished."Major" loops are obtained by sweeping the applied field beyond the saturation field H sat , above which the system is said to be fully saturated and its magnetization M(H) is a single-valued function of the applied field H; "minor" loops are obtained when the cycle is limited to fields near and below H sat . Many studies were devoted to the macroscopic and microscopic repeatability of minor and major hysteresis loops and effects of disorder on cycle-to-cycle memory [1,2]. Macroscopically the major loops repeat themselves in successive cycles, however it was appreciated [3,4] that disorder induces memory in the microscopic magnetic domain configurations from one cycle of the hysteresis loop to the next, even when H sat was crossed. Successive minor loops are usually reasonably reproducible, although changes of size and shape were observed [5][6][7]. Nevertheless these finite perturbations did not undermine a generally accepted view that macroscopic hysteresis loops are repeatable. It came therefore as a surprise when Berger et al. [8] reported major cumulative expansion of successive minor hysteresis loops in Co/Pt and Co/Pd multilayers even up to four times their initial area. The phenomenon was explained in terms of successive accumulation of small nucleation domains, i.e. microscopic areas of reversed magnetization that act as nuclei for the subsequent macroscopic magnetization reversal [8,9]. The reversals at all but the first cycle do not start anew from a fully saturated state but from a preconfigured state in which nuclei for domain expansion are locally conserved. Conservation and accumulation of the nuclei can happen if the system responds asymmetrically in forward and reverse field orientations such that small domains appear to be substantially more stable toward annihilation in an opposite field than toward expansion in a forward field.In this paper we shall de...

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“…It is common practice to employ the Fatuzzo-Labrune theory [17,19] to interpret magnetization reversal in thin films. The theory uses two microscopic phenomena:…”

Section: Magnetization Reversal At Constant Magnetic Fieldmentioning

confidence: 99%

“…A typical activation volume V a can be estimated from an exponential field dependence of t 50 on the magnetic field [17,21] ( )…”

Section: Magnetization Reversal At Constant Magnetic Fieldmentioning

confidence: 99%

Dynamics of successive minor hysteresis loops

2012

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“…In conventional magnetic films with uniform magnetic anisotropy, magnetic switching proceeds by nucleation of reversed domains and subsequent domain growth via lateral domain wall motion. Models describing thermally activated magnetization reversal and magnetic domain wall motion use parameters that vary with the magnetic anisotropy energy and random fluctuations thereof, while the energetics of magnetic domain walls is not specifically taken into account [1][2][3]. Since the density of domain walls is often low and their spin structure and energy remain nearly constant during domain growth, this omission is justified for most ferromagnetic systems.…”

Section: Introductionmentioning

confidence: 99%

Influence of elastically pinned magnetic domain walls on magnetization reversal in multiferroic heterostructures

Casiraghi¹,

Rincón-Domínguez²,

Rößler³

et al. 2015

Phys. Rev. B

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In elastically coupled multiferroic heterostructures that exhibit full domain correlations between ferroelectric and ferromagnetic subsystems, magnetic domain walls are firmly pinned on top of ferroelectric domain boundaries. In this work, we investigate the influence of pinned magnetic domain walls on the magnetization reversal process in a Co 40 Fe 40 B 20 wedge film that is coupled to a ferroelectric BaTiO 3 substrate via interface strain transfer. We show that the magnetic field direction can be used to select between two distinct magnetization reversal mechanisms, namely, (1) double switching events involving alternate stripe domains at a time or (2) synchronized switching of all domains. Furthermore, scaling of the switching fields with domain width and film thickness is also found to depend on the field orientation. These results are explained by considering the dissimilar energies of the two types of pinned magnetic domain walls that are formed in the system.

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“…Как правило, термоактивированное перемагничивание ферромагнетиков определяется зародышеобразованием фазы обратной намагниченности [12] и/или движением доменных стенок [13]. Оба эти процесса учтены в мо-дели Фаттузо−Лабруне [14], описывающей релаксацию намагниченности тонких пленок.…”

Section: Discussionunclassified

Конкуренция доменных стенок и фазы обратной намагниченности в магнитной релаксации спинового переключателя Pt/Co/Ir/Co/Pt

Моргунов¹,

L’vova²,

Hamadeh³

et al. 2018

Физика Твердого Тела

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В многослойной гетероструктуре Pt/Co/Ir/Co/Pt/GaAs наблюдается длительная (до нескольких часов) магнитная релаксация между двумя стабильными состояниями намагниченности системы. Перемагничивание слоев гетерострукуры происходит как за счет образования зародышей доменов обратной намагничеснности, так и в результате их дальнейшего роста посредством движения доменных стенок. Конкуренция между этими двумя процессами обуславливает неэкспоненциальный характер магнитной релаксации. При 300 K вклады этих процессов в релаксацию намагниченности сопоставимы, в то время как при температурах ниже 200 K вклад зародышеобразования подавляется и магнитная релаксация происходит в результате движения доменных стенок.Работа выполнена при поддержке гранта 3.1992.2017/ПЧ в рамках конкурса научных проектов, выполня-емых научными коллективами исследовательских центров и (или) научных лабораторий образовательных организаций высшего образования.

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Time dependence of the magnetization process of RE-TM alloys

Cited by 196 publications

References 9 publications

Dynamics of successive minor hysteresis loops

Dynamics of successive minor hysteresis loops

Influence of elastically pinned magnetic domain walls on magnetization reversal in multiferroic heterostructures

Конкуренция доменных стенок и фазы обратной намагниченности в магнитной релаксации спинового переключателя Pt/Co/Ir/Co/Pt

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