Modification of the ferromagnetic anisotropy and exchange bias field of NiFe/CoO/Co trilayers through the CoO spacer thicknesses

Exchange bias and interlayer exchange coupling are interface driven phenomena. Since an ideal interface is very challenging to achieve, a clear understanding of the chemical and magnetic natures of interfaces is pivotal to identify their influence on the magnetism. We have chosen NiFe/CoO(t )/Co trilayers as a model system, and identified non-stoichiometric Ni-ferrite and Co-ferrite at the surface and interface, respectively. These ferrites, being ferrimagnets typically, should influence the exchange coupling. However, in our trilayers the interface ferrites were found not to be ferro- or ferri-magnetic; thus having no observable influence on the exchange coupling. Our analysis also revealed that (i) interlayer exchange coupling was present between NiFe and Co even though the interlayer thickness was significantly larger than expected for this phenomenon to happen, and (ii) the majority of the CoO layer (except some portion near the interface) did not contribute to the observed exchange bias. We also identified that the interlayer exchange coupling and the exchange bias properties were not interdependent.

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“…The Ni 80 Fe 20 /CoO/Co trilayers were deposited on SiO 2 substrates using a dual ion-beam technique [18,22]. A Kaufman ion source (800 V, 7. )…”

Section: Experimental Methodsmentioning

confidence: 99%

Interface mixing and its impact on exchange coupling in exchange biased systems

Manna

Skoropata

Ting

et al. 2016

J. Phys.: Condens. Matter

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“…As shown in Figure 5a, the spin texture of the hard magnetic layer is the Néel‐type skyrmion. The strength of interlayer exchange between two magnetic layers can be tailored by adding spacer layer (nonmagnetic spacing layer such as Ru, Rh, or Ir; antiferromagnetic such as NiO, Cr 2 O 3 , or Cr), [ 31,32 ] or via adjusting the working temperature [ 32 ] and controlling the interface roughness. [ 33 ] Particularly, in Co(3 nm)/Cr/Fe(10 nm) trilayers, the two magnetic layers have been found to decouple at high temperature.…”

Section: Stability Of the Artificial Skyrmionmentioning

confidence: 99%

Influence of Material Parameters on the Stability of Artificial Skyrmion in Hard/Soft Magnetic Bilayers

Liu

Qian

Zhu

2021

Physica Status Solidi (b)

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Herein, the influence of material parameters on the core diameter of the artificial skyrmions in hard magnetic/soft magnetic bilayer thin film is investigated. It is found that the perpendicular magnetic anisotropy (PMA) constant and the interlayer exchange constant play a key role in the realization of artificial skyrmions. Through simulation, the PMA constant of the hard magnetic materials should be between 1.0 × 105 and 4.5 × 105 J m−3. Therefore, some rare earth materials with high magnetic anisotropy or other materials with low magnetic anisotropy do not meet the requirement. The initial skyrmion spin texture is Bloch‐type artificial skyrmion in the hard/soft magnetic bilayer system. In the presence of 1.0–1.5 × 105 J m−3 PMA constant and 0 J m−1 interlayer exchange constant, the Néel‐type artificial skyrmions are formed in the hard/soft magnetic bilayer system. The size of the hard magnetic layer material has little effect on the stability of skyrmions, so the stability of skyrmions should mainly be adjusted with the PMA of the hard magnetic materials or by changing the material types.

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“…The tuning of magnetic properties (hysteresis loops shape, coercivity, and exchange bias) of thinfilm structures with exchange bias for different applications can be realized by changing either the deposition conditions or the method of sample synthesis [7,12,13]. To observe a controllable stepwise hysteresis loop for an exchange-coupled structure, it should typically comprise of at least two ferromagnetic layers [14][15][16]. Two FM layers can possess either both in-plane or out-of-plane anisotropies, or one can have in-plane and the other out-of-plane anisotropy [17][18][19][20].…”

Section: Introductionmentioning

confidence: 99%

Inhomogeneous magnetic field influence on magnetic properties of NiFe/IrMn thin film structures

Gritsenko

Omelyanchik

Berg

et al. 2019

Journal of Magnetism and Magnetic Materials

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We demonstrate how the configuration and magnitude of a magnetic field, applied during magnetron sputtering of a NiFe/IrMn bilayer, influence the magnetic properties of the structure, such as hysteresis loop shape, coercivity, and exchange bias. Furthermore, we illustrate that it is possible to create a stepwise hysteresis loop in the sample's region with the highest field gradient. The found features can be used for future sensor applications.

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Modification of the ferromagnetic anisotropy and exchange bias field of NiFe/CoO/Co trilayers through the CoO spacer thicknesses

Cited by 10 publications

References 18 publications

Interface mixing and its impact on exchange coupling in exchange biased systems

Interface mixing and its impact on exchange coupling in exchange biased systems

Influence of Material Parameters on the Stability of Artificial Skyrmion in Hard/Soft Magnetic Bilayers

Inhomogeneous magnetic field influence on magnetic properties of NiFe/IrMn thin film structures

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