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چکیده
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Optical control of magnetic properties in exchange coupled photostrictive/ferromagnetic heterostructures is of great fundamental and technical interest for application in information storage, spintronic and microwave magnetic devices. In the present research, an optical modification of exchange bias field and magnetic properties of Fe2B/BiFeO3 heterostructure has been reported. A Fe2B/BiFeO3 bilayer and a BiFeO3 single-layer were deposited on (001)-SrTiO3 substrate by pulsed laser deposition technique. Magneto-optical hysteresis loops and x-ray diffraction pattern of the samples were recorded under light illumination with a wavelength of 405 nm at different intensities. Recorded hysteresis loops showed exchange bias coupling between ferromagnetic Fe2B and antiferromagnetic BiFeO3 layers. In addition, the results showed optically-induced changes in exchange bias and coercive fields. A critical point, in the variation of the exchange bias field with light intensity, was observed at 330 ± 10 mW/cm2. The behaviour of the exchange bias field was changed at this critical point with enhancement of the light intensity. Furthermore, the X-ray diffraction results indicated that light illumination led to an out of plane tensile strain in the BiFeO3 layer and this strain led to manipulation of the BiFeO3 magnetization. Therefore, the observed optically-induced changes can be related to the photo-induced strain in the BiFeO3 layer.
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