Tunnel magnetoresistance of 604% at 300K by suppression of Ta diffusion in CoFeB∕MgO∕CoFeB pseudo-spin-valves annealed at high temperature

Ikeda, Shoji; Hayakawa, Jun; Ashizawa, Yoshito; Lee, Y. M.; Miura, Katsuya; Hasegawa, H.; Tsunoda, Masakiyo; Matsukura, F.; Ohno, Hideo

doi:10.1063/1.2976435

Cited by 1,356 publications

(788 citation statements)

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“…Thus, we expect that the functionality of any device could be enhanced in which layer magnetizations are reoriented relative to each other. This includes GMR and TMR spin valves [ 35 ] for magnetic sensors, magnetoresistive random access memory (MRAM) cells and a multitude of systems that are based on spin-transfer torque. The large parameter range of coercivities and easy axes orientations possible in one single device will lead to qualitative advances, e.g., new types of 3D multilevel magnetic memory cells [ 36,37 ] and the design of switchable ferromagnetic/nonmagnetic hybrid structures (e.g., ferromagnet/superconductor hybrids [ 38 ] ).…”

Section: Resultsmentioning

confidence: 99%

Spin‐Structured Multilayers: A New Class of Materials for Precision Spintronics

Schlage

Bocklage

Erb

et al. 2016

Adv Funct Materials

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7423wileyonlinelibrary.com extensively explored to maximize the magnitude of the magnetoresistive signal, which is defi ned as the normalized difference of the electrical resistance in the antiparallel and parallel magnetic confi guration of the trilayer. The basic GMR and TMR characteristics of spintronic devices and thus their functionalities, however, did not signifi cantly change during the last decade. This is due to conventional magnetic multilayer design and its limitations based on the interplay of accessible magnetic anisotropy contributions. Here, we show that oblique incidence deposition (OID) can be used in an elegant way to achieve full control on the magnetic anisotropy in every individual layer of such magnetoresistive multilayer stacks for the fi rst time. The additional shape anisotropy component introduced via OID allows for arbitrarily crossed magnetic easy axes with adjustable switching fi elds and opens a path for customized spintronic devices with conceptually new functionalities.So far, two major approaches have been pursued to engineer fi eld-dependent relative magnetic confi gurations of two ferromagnetic layers. In the fi rst case, one of the ferromagnetic layers either exhibits an enhanced coercive fi eld or is magnetically pinned (exchange biased) by an additional antiferromagnetic layer of high magnetic anisotropy. Thus, only the magnetically uncoupled free layer follows small external fi elds, causing a change of the magnetic confi guration and the magnetoresistance. [ 13 ] In the second approach, an interlayer exchange coupling, the Ruderman-Kittel-Kasuya-Yoshida (RKKY) interaction, is used to align both layers relative to each other. [ 14 ] The interlayer coupling defi nes the magnetic saturation behavior and hence the functionality of the trilayer. In conventional systems, only parallel or antiparallel orientations of the ferromagnetic layers are reliably achieved. Effi cient RKKY coupling is observed for particular material combinations only and depends very sensitively on the interlayer thickness. [ 15,16 ] Therefore, conventional magnetic multilayer design is restricted to a limited number of magnetic confi gurations in the trilayers which constrains the design and control of magnetic spin structures that are available for realizing particular magnetoelectronic responses.Our approach enables one to realize and tune magnetic and magnetoresistive properties in spintronic multilayer systems that exceed the potential of conventional approaches by far. The technique is not based on exchange-bias or interlayer coupling and is not affected by their limitations. Every ferromagnetic layer of arbitrary chemical composition, as a constituent either Spin-Structured Multilayers: A New Class of Materials for Precision SpintronicsKai Schlage , * Lars Bocklage , Denise Erb , Jade Comfort , Hans-Christian Wille , and Ralf Röhlsberger * Magnetoelectronic multilayer devices are widely used in today's information and sensor technology. Their functionality, however, is limited by the inherent prop...

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Section: Resultsmentioning

confidence: 99%

Spin‐Structured Multilayers: A New Class of Materials for Precision Spintronics

Schlage

Bocklage

Erb

et al. 2016

Adv Funct Materials

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“…Amorphous CoFeB films have been a subject of extensive studies due to its low coercivity, large saturation magnetization [21,22] and high spin polarization [23], which were widely used in theory research [24,25], magnetic tunnel junctions [26] and spin transfer torque devices [27]. The proper scaling of amorphous CoFeB in the dirty regime without consideration of the quantum correction can be explained by the combination of extrinsic and intrinsic mechanisms quantitatively [28].…”

Section: Introductionmentioning

confidence: 99%

Scaling of anomalous Hall effect in amorphous CoFeB films with accompanying quantum correction

Zhang

Wang

et al. 2015

Solid State Communications

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This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting galley proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

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“…It is interesting to note that such dependence of the magnetoresistance amplitude on the direction of the current with respect to the magnetization has already been observed with the giant magnetoresistance in spin-valves [16]. In MTJs, from a general experimental point of view, the TMR of MgO based in-plane magnetized MTJs has reached values above 600% [17,18]. In contrast, the largest TMR of MgO based out-of-plane magnetized MTJs is in the range (200-350% [19]), significantly lower than the values obtained in their in-plane magnetized counterparts.…”

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confidence: 98%

“…In theory, the TMR amplitude predicted by ab-initio calculations neglecting spinorbit [14] is much larger than the experimentally obtained values. In experiments, the TMR amplitude is limited by defects which can have several origins: interdiffusion of metallic species in the composite magnetic electrodes [17,18,20], structural defects associated with fcc/bcc in-stack structural competition [21], presence of dislocations in MgO associated with Fe(Co)-MgO crystallographic mismatch, adsorbed water molecules etc.…”

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confidence: 99%