Magnetoelectric Induced Switching of Perpendicular Exchange Bias Using 30-nm-Thick Cr2O3 Thin Film

Magnetoelectric (ME) effect is a result of the interplay between magnetism and electric field and now, it is regarded as a principle that can be applied to the technique of controlling the antiferromagnetic (AFM) domain state. The ME-controlled AFM domain state can be read out by the magnetization of the adjacent ferromagnetic layer coupled with the ME AFM layer via exchange bias. In this technique, the reduction in the ME layer thickness is an ongoing challenge. In this paper, we demonstrate the ME-induced switching of exchange bias polarity using the 30-nm thick ME Cr2O3 thin film. Two typical switching processes, the ME field cooling (MEFC) and isothermal modes, are both explored. The required ME field for the switching in the MEFC mode suggests that the ME susceptibility (α33) is not deteriorated at 30 nm thickness regime. The isothermal change of the exchange bias shows the hysteresis with respect to the electric field, and there is an asymmetry of the switching field depending on the switching direction. The quantitative analysis of this asymmetry yields α33 at 273 K of 3.7 ± 0.5 ps/m, which is comparable to the reported value for the bulk Cr2O3.

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Exchange Bias and Training Effect in Polycrystalline Antiferromagnetic/Ferromagnetic Bilayers

MRS Proceedings ◽

10.1557/proc-746-q7.6 ◽

2002 ◽

Vol 746 ◽

Author(s):

Markus Kirschner ◽

Dieter Suess ◽

Thomas Schrefl ◽

Josef Fidler

Keyword(s):

Layer Thickness ◽

Exchange Bias ◽

Ferromagnetic Layer ◽

Bias Field ◽

Training Effect ◽

Hysteresis Cycle ◽

Weak Exchange ◽

Antiferromagnetic Layer ◽

20 Nm ◽

And Training

ABSTRACTExchange bias and training effect are simulated for IrMn/NiFe bilayers. As a function of the thickness of the antiferromagnet the bias field shows a maximum for a thickness of 22 nm. For decreasing antiferromagnetic thickness the domain wall energy approaches zero. For large thicknesses the high anisotropy energy hinders switching of the antiferromagnetic grains resulting in weak bias. Starting from the field cooled state as initial configuration a bias field of about 8 mT is obtained assuming a antiferromagnetic layer thickness of 20 nm, a ferromagnetic layer thickness of 10 nm, and a grain size of 10 nm. The next hysteresis cycle shows a reduction of the bias field by about 65%. Exchange bias and training effect in fully compensated antiferromagnet/ferromagnet bilayers are explained with a simple micromagnetic model. The model assumes no defects except for grain boundaries, and coupling is due to spin flop at a perfect interface. The simulations show that a weak exchange interaction between randomly oriented antiferromagnetic grains and spin flop coupling at a perfectly compensated interface are sufficient to support exchange bias.

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Role of anti-ferromagnetic layer thickness in exchange bias: case study of Co/CoO with Kerr microscopy

Materials Research Express ◽

10.1088/2053-1591/ab0ca7 ◽

2019 ◽

Vol 6 (6) ◽

pp. 066109 ◽

Cited By ~ 1

Author(s):

Zaineb Hussain ◽

V Raghavendra Reddy

Keyword(s):

Layer Thickness ◽

Exchange Bias ◽

Ferromagnetic Layer

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Simulations of the Domain State Model

MRS Proceedings ◽

10.1557/proc-746-q7.4 ◽

2002 ◽

Vol 746 ◽

Author(s):

U. Nowak ◽

A. Misra ◽

K. D. Usadel

Keyword(s):

Monte Carlo ◽

Monte Carlo Simulations ◽

Exchange Bias ◽

Ferromagnetic Layer ◽

State Model ◽

Positive Bias ◽

Initial Field ◽

The Past ◽

Domain State ◽

Antiferromagnetic Layer

ABSTRACTThe domain state model for exchange bias consists of a ferromagnetic layer exchange coupled to an antiferromagnetic layer. In order to model a certain degree of disorder within the bulk of the antiferromagnet, the latter is diluted throughout its volume. Extensive Monte Carlo simulations of the model were performed in the past. Exchange bias is observed as a result of a domain state in the antiferromagnetic layer which develops during the initial field cooling, carrying a remanent domains state magnetization which is partly irreversible during hysteresis. A variety of typical effects associated with exchange bias like, e. g., its dependence on dilution, positive bias, temperature and time dependences as well as the dependence on the thickness of the antiferromagnetic layer can be explained within this model.

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Resistance Changes of (La, Sr)MnO3 Thin Film via Exchange Bias Tuning by the Application of an External Electric Field

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.421-422.107 ◽

2009 ◽

Vol 421-422 ◽

pp. 107-110

Author(s):

Takeshi Yokota ◽

Shotaro Murata ◽

Shinya Kito ◽

Manabu Gomi

Keyword(s):

Thin Film ◽

Electric Field ◽

Exchange Interaction ◽

External Electric Field ◽

Exchange Bias ◽

Interaction Strength ◽

Bias Field ◽

Magnetization Curves ◽

Resistance Change ◽

Lsmo Film

We have investigated the relationships between the electric field-induced resistance change and the strength of the exchange interaction of the Cr2O3/ La0.7Sr0.3MnO3 (LSMO) magnetic hetero system. The hetero system subjected to field cooling (FC) showed a positive shift in the magnetization curves due to an exchange bias. The exchange bias field changed depending on the FC field. Resulting from the exchange behaviors, the resistance of LSMO film was changed by the application of an electric field to the Cr2O3 gate. This resistance change is more likely due to the interface interaction strength between the Cr2O3 and LSMO film

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Antiferromagnetic Layer Thickness Dependence of Exchange Bias in Sputter-Deposited Co/CoO/Co Trilayer

Materials Science Forum ◽

10.4028/www.scientific.net/msf.675-677.1263 ◽

2011 ◽

Vol 675-677 ◽

pp. 1263-1266

Author(s):

Jian Wang ◽

Shinji Muraishi ◽

Ji Shi ◽

Yoshio Nakamura

Keyword(s):

Layer Thickness ◽

Exchange Bias ◽

Exchange Coupling ◽

Sandwich Structure ◽

Thickness Dependence ◽

Structural Defects ◽

Domain State ◽

Antiferromagnetic Layer ◽

Sputter Deposited ◽

The One

We have used ferromagnet/antiferromagnet/ferromagnet sandwich structure to probe the antiferromagnetic layer thickness dependence of exchange bias in sputter-deposited Co/CoO/Co trilayer. The exchange coupling occurring at the upper ferromagnetic/antiferromagnetic interface is always found to be stronger than the one at the lower antiferromagnetic/ferromagnetic interface. The grain growth with increasing antiferromagnetic layer thickness can lead to a gradient of grain size distribution through the whole antiferromagnetic layer. Consequently, the relatively large grains at the upper interface would results in a rougher interface which we treat as structural defects and can significantly enhance exchange bias through domain state model. The slightly decrease of exchange coupling with increasing antiferromgnetic layer thickness indicates that the exchange bias is only governed by the grains that are thermally stable but whose anisotropy energy is low enough to be set.

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Phase Transition-Induced Modulation of Exchange Bias in Fe/BiFeO3 Bilayers

Science of Advanced Materials ◽

10.1166/sam.2020.3710 ◽

2020 ◽

Vol 12 (5) ◽

pp. 701-706

Author(s):

Liyan Wang ◽

Zongguo Li ◽

Cong Wang ◽

Xue Gong ◽

Changzheng Wang

Keyword(s):

Phase Transition ◽

Electric Field ◽

Exchange Interaction ◽

Exchange Bias ◽

Domain Walls ◽

Ferromagnetic Layer ◽

Transition Process ◽

Phase Transition Process ◽

Antiferromagnetic Layer ◽

Ferromagnetic Magnetization

Many of researches indicate that epitaxial BiFeO3 (BFO) films deposited on LaAlO3 (LAO) substrate undergo strain-driven phase transition from a tetragonal-like phase (T-BFO) to a rhombohedral-like phase (R-BFO), and a mixed phase (M-BFO) that T-BFO coexists with R-BFO forms in the phase transition process. It is necessary to explore how BFO phase transition affects the exchange bias in ferromagnet (FM)/BFO bilayers. In our studies, aforementioned BFO phase transition is accomplished by varying BFO films thickness. Using 5 nm-thick Fe as ferromagnetic layer deposited on 9–354 nm-thick BFO as antiferromagnetic layer, the exchange bias in Fe/BFO bilayers exhibits that Fe/M-BFO bilayers shows smaller exchange bias than Fe/T-BFO and Fe/R-BFO bilayers. We ascribed the effect of the BFO phase transition on the exchange bias to the domain walls caused by the exchange interaction between T-BFO and R-BFO across their boundaries. Additionally, for the same reason, the coercivity also exhibits the same variation trend as the exchange bias does. Our studies will help to promote the application of controlling the ferromagnetic magnetization by the electric field.

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Coexistence of perpendicular and in-plane exchange bias using a single ferromagnetic layer in Pt/Co/Cr/CoO thin film

EPL (Europhysics Letters) ◽

10.1209/0295-5075/114/17008 ◽

2016 ◽

Vol 114 (1) ◽

pp. 17008 ◽

Cited By ~ 1

Author(s):

Mustafa Öztürk ◽

Erdem Demirci ◽

Mustafa Erkovan ◽

Osman Öztürk ◽

Numan Akdoğan

Keyword(s):

Thin Film ◽

Exchange Bias ◽

Ferromagnetic Layer

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Application of EDS Technique for OSP Film Thickness Measurement

ISTFA 2006: Conference Proceedings from the 32nd International Symposium for Testing and Failure Analysis ◽

10.31399/asm.cp.istfa2006p0193 ◽

2006 ◽

Author(s):

Prong Kongsubto ◽

Sirarat Kongwudthiti

Keyword(s):

Thin Film ◽

Quantitative Analysis ◽

Joint Strength ◽

Critical Factor ◽

Thickness Measurement ◽

Ic Manufacturing ◽

And Control ◽

Film Thickness Measurement ◽

Non Destructive

Abstract Organic solderability preservatives (OSPs) pad is one of the pad finishing technologies where Cu pad is coated with a thin film of an organic material to protect Cu from oxidation during storage and many processes in IC manufacturing. Thickness of OSP film is a critical factor that we have to consider and control in order to achieve desirable joint strength. Until now, no non-destructive technique has been proposed to measure OSP thickness on substrate. This paper reports about the development of EDS technique for estimating OSP thickness, starting with determination of the EDS parameter followed by establishing the correlation between C/Cu ratio and OSP thickness and, finally, evaluating the accuracy of the EDS technique for OSP thickness measurement. EDS quantitative analysis was proved that it can be utilized for OSP thickness estimation.

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