Magneto-optical Kerr effect and magnetization structure of permalloy microparticles under mechanical stress

T.F. Khanipova, D.A. Bizyaeva, A.A. Bukharaeva,b, V.V. Chirkova, A.P. Chuklanova, N.I. Nurgazizova*

aZavoisky Physical-Technical Institute, Kazan Scientific Center, Russian Academy of Sciences, Kazan, 420029 Russia

bKazan Federal University, Kazan, 420008 Russia

E-mail: *niazn@mail.ru

Received November 29, 2017

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Abstract

In this work, changes in the domain structure of planar permalloy microparticles under mechanical stress have been studied. For this purpose, an array of particles under mechanical stress has been formed on the silicon substrate. In addition, samples with an array of unstressed particles have been made. Using the samples, the magnetic structure has been visualized by magnetic force microscopy and hysteresis loops have been obtained by the method of magneto-optical Kerr effect. It has been found that an easy magnetization axis appears in the stressed samples due to uniaxial anisotropy caused by the mechanical stress of the particles. The axis direction coincides with the direction of particle compression. At the same time, the distribution of magnetization observed in the unstressed particles is determined mainly by the shape anisotropy.

Keywords: magnetoelastic effect, magnetic-force microscopy, magneto-optical Kerr effect, ferromagnetic microparticles, permalloy

Acknowledgments. The study was supported by the Russian Foundation for Basic Research (project no. 17-08-00915).

Figure Captions

Fig. 1. Hysteresis loops obtained by the method of magneto-optical Kerr effect for unstressed (solid lines) and stressed (dashed lines) particles at the external magnetic field direction along the easy magnetization axis ( a) and along the hard magnetization axis ( b). Angular dependencies of the normalized remnant magnetization ( c) and coercive field of particles ( d).

Fig. 2. MFM image of two Py particles and the magnetization structure corresponding to them in the following cases: unstressed particles without the external magnetic field ( a), stressed particles without the field ( b), unstressed particles in the field –15 E ( c), stressed particles in the field –15 E ( d), unstressed particles (quasisingle domain) in the field –40 E ( e), uniformly magnetized in the field –100 E ( f). The direction of stressed particle compression is shown with white arrows. Scanning field is 22 * 9 μm.

References

1. Morozov A.I. Ferromagnetic magnetization switching by an electric field: A review. Phys. Solid State, 2014, vol. 56, no. 5, pp. 865–872. doi: 10.1134/S1063783414050199.

2. Belyaev B.A., Izotov A.V. Ferromagnetic resonance study of the effect of elastic stresses on the anisotropy of magnetic films. Phys. Solid State, 2007, vol. 49, no. 9, pp. 1731–1739. doi: 10.1134/S106378340709020X.

3. Bizyaev D.A., Bukharev A.A., Kandrashkin Yu.E., Mingalieva L.V., Nurgazizov N.I., Khanipov T.F. The magnetoelastic effect in permalloy particles. Tech. Phys. Lett., 2016, vol. 42, no. 10, pp. 1034–1037. doi: 10.1134/S1063785016100187.

4. Peng R.-C., Wang J.J., Hu J.-M., Chen L.-Q., Nan C.-W. Electric-field-driven magnetization reversal in square-shaped nanomagnet-based multiferroic heterostructure. Appl. Phys. Lett., 2015, vol. 106, no. 14, art. 142901, pp. 1–5. doi: 10.1063/1.4917228.

5. Finizio S., Foerster M., Buzzi M., Kruger B., Jourdan M., Vaz C.A.F., Hockel J., Miyawaki T., Tkach A., Valencia S., Kronast F., Carman G.P., Nolting F., Klaui M. Magnetic anisotropy engineering in thin film Ni nanostructures by magnetoelastic coupling. Phys. Rev. Appl., 2014, vol. 1, no. 2, art. 021001, pp. 1–6. doi: 10.1103/PhysRevApplied.1.021001.

6. Kumar D., Singh S., Vishawakarma P., Dev A.S., Reddy V.R., Gupta A. Tailoring of in-plane magnetic anisotropy in polycrystalline cobalt thin films by external stress. J. Magn. Magn. Mater., 2016, vol. 418, pp. 99–106. doi: 0.1016/j.jmmm.2016.03.072.

7. Dai G., Zhan Q., Yang H., Li R.-W. Controllable strain-induced uniaxial anisotropy of Fe81Ga19 films deposited on flexible bowed-substrates. J. Appl. Phys., 2013, vol. 114, no. 17, art. 173913, pp. 1–6. doi: 10.1063/1.4829670.

8. The Object Oriented MicroMagnetic Framework (OOMMF) project at ITL/NIST. Available at: http://math.nist.gov/oommf/.

9. Ovchinnikov D.V., Bukharaev A.A. Computer simulation of magnetic force microscopy images with a static model of magnetization distribution and dipole-dipole interaction. Tech. Phys., 2001, vol. 46, no. 8, pp. 1014–1019. doi: 10.1134/1.1395123.

10. Vonsovskii S.V. Magnetizm [Magnetism]. Moscow, Nauka, 1971. 1032 p. (In Russian)


For  citation: Khanipov T.F., Bizyaev D.A., Bukharaev A.A., Chirkov V.V., Chuklanov A.P., Nurgazizov  N.I.  Magneto-optical  Kerr  effect  and  magnetization  structure of permalloy microparticles under mechanical stress. Uchenye Zapiski Kazanskogo Universiteta. Seriya Fiziko-Matematicheskie Nauki, 2018, vol. 160, no. 1, pp. 135–144. (In Russian)


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