Magnetic properties of Fe-Bi films Patrin, G S; Yakovchuk, V Yu; Yarikov, S A ...
Journal of physics. Conference series,
11/2019, Letnik:
1389, Številka:
1
Journal Article
Recenzirano
Odprti dostop
In the paper the results of experimental studies of film structures in the Fe-Bi system are presented. By the method of electron magnetic resonance, it is shown that for bilayer structures the ...magnetic state depends on the order of deposition of the magnetic and non-magnetic layers. In the three-layer structures, the effect of exchange bias was found, the magnitude of that depends on the thickness of the bismuth layer.
This paper presents the results of measuring the main parameters of the ferromagnetic and spin-wave resonance spectra (resonant field, linewidth, and intensity) of single-layer permalloy films at ...various angles in the out-of-plane orientation. The effect of the type of surface conditions on the angular dependence of the intensity ratio of adjacent modes is studied. A correspondence is established between the angle of the applied constant magnetic field with respect to the normal to the film and the change in the oscillation type from uniform to nonuniform. The revealed features of the angular dependences of the resonant field and the intensity of the spectral peak can be successfully used in the identification of microwave spectra. The fundamental magnetic parameters (effective magnetization, exchange interaction constant, surface anisotropy constant, and perpendicular anisotropy field) were determined.
The features of the magnetic state of an array of parallel oriented permalloy ribbons are discussed. The arrays are made by explosive lithography. The ribbons have a thickness of 180 nm, a width of ...2.8 µm, and a length of about 4 mm. The distance between ribbons in different samples varies in the range from 300 nm to 4 μm. It is found that the ribbons in the regions far from the end faces are in a single-domain state with small-angle ripples, the magnetization distribution of which correlates with inhomogeneities of the ribbon side surfaces. Moreover, there is a distinct relationship in the spatial distribution of the ripples between adjacent ribbons with a relatively small distance between them. This makes it possible to evaluate the role of the magnetostatic coupling of magnetic subsystems of array elements and to estimate the characteristic value of the random stray field that pins the magnetization.
The interlayer coupling in three-layer FeNi/Bi/FeNi films is studied by electron magnetic resonance. The magnetic anisotropy at the permalloy–bismuth interface is shown to play a significant role in ...the formation of the magnetic state of the film structure. The interlayer coupling oscillation period is found to be about 8 nm. The interlayer coupling and the interface anisotropy and their temperature dependences are determined.
The variations of the structural and magnetic properties of Bi/Mn/Bi and Mn/Bi/Mn trilayer film systems of equiatomic composition in the process of vacuum annealing are studied. The annealing of ...Bi/Mn/Bi films at a temperature of 270°C for an hour results in the synthesis of the well-studied highly oriented low-temperature LT-MnBi(001) phase with the perpendicular magnetic anisotropy
K
u
∼ 1.1 × 10
7
erg/cm
3
and coercivity
H
C
∼ 1.5 kOe. In contrast to Bi/Mn/Bi, polycrystalline LT-MnBi nanoclusters are formed in Mn/Bi/Mn films under the same annealing conditions. A high rotatable magnetic anisotropy exceeding the shape anisotropy is detected in the films under consideration: the easy axis of anisotropy with the inclusion of the delay angle in magnetic fields above the coercivity
H
>
H
C
= 9.0 kOe can be oriented in any spatial direction. It is shown that the nature of rotatable magnetic anisotropy is due to the structural coexistence of epitaxially coupled LT-MnBi and QHTP-Mn
1.08
Bi phases. The reported experimental results indicate the existence of a new class of ferromagnetic film media with the spatially tunable easy axis.
Results of the experimental investigation of two-layer films in the Fe–Bi system are presented. It is found that the order of sequential deposition of the magnetic and nonmagnetic layers influences ...both the character of magnetization process and the magnetic resonance behavior. The obtained results are explained by the formation of a strongly anisotropic sublayer of nanogranular iron in the Bi/Fe film structure.
Film structures in the Fe–Bi system have been studied experimentally. The magnetic state of the two-layer structures is shown by electron magnetic resonance to be dependent on the order of depositing ...magnetic and nonmagnetic layers. The three-layer structures demonstrate the effect of the exchange bias, the value of which is dependent on the bismuth interlayer thickness.
We report on the results of investigations of the optical and magnetooptical properties of Dy
x
Co
1 –
x
/Bi/Py (Py is permalloy) trilayers. The temperature dependence of the magnetization has been ...examined using the magnetooptical Kerr effect and the optical refractive and absorption indices have been measured by spectral ellipsometry. It is shown that the thickness of the bismuth spacer affects the exchange coupling between the permalloy and DyCo layers, which manifests itself in the change in the magnetization compensation temperature and in the character of the exchange coupling.
The interlayer interactions in multilayer systems with a non-magnetic semimetallic interlayer are great of interest. The magnetic and structural properties of the Dy
x
Co
1-x
/Bi/Py systems (17 <
x
...< 26 at.%) have been studied. The temperature dependences of magnetization in the range 4.2–300 K were measured for the first time. The influence of the bismuth interlayer thickness on the exchange interaction between the DyCo and Py layers was found as well as the critical value of its thickness. The obtained atypical value of the period of exchange bias oscillations was explained by the formation of bismuth compounds with dysprosium–pnictogenides at bismuth thicknesses below the critical value. The interface was investigated by spectral ellipsometry in the range 2–5 eV. The information on the structure of the surface obtained by atomic force microscopy was used to create a multilayer model for fitting experimental ellipsometric data. Analysis of the optical properties showed that pnictogenide Dy
3
Bi
2
is formed at the interface, which affects the general magnetic state of the samples studied.
Chiral magnetism that manifests in the existence of skyrmions or chiral domain walls offers an alternative way for creating anisotropies in magnetic materials that might have large potential for ...application in future spintronic devices. Here we show experimental evidence for an alternative type of in-plane exchange-bias effect present at room temperature that is created from a chiral 90 degrees domain wall at the interface of a ferrimagnetic-ferromagnetic Dy-Co/Ni-Fe bilayer system. The chiral interfacial domain wall forms due to the exchange coupling of Ni-Fe and Dy-Co at the interface and the presence of Dzyaloshinskii-Moriya interaction in the Dy-Co layer. As a consequence of the preferred chirality of the interfacial domain wall, the sign of the exchange-bias effect can be reversed by changing the perpendicular orientation of the Dy-Co magnetization. The chirality-created tunable exchange bias in Dy-Co/Ni-Fe is very robust against high in-plane magnetic fields (mu H-0 <= 6 T) and does not show any aging effects. Therefore, it overcomes the limitations of conventional exchange-bias systems.
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