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The temperature-sensitivity of a critical electric field induced magnetic easy- axis reorientation/ferromagnetic ferroelectric layered heterostructures

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We have investigated the effects of temperature on the magnetic easy axis reorientation (EARs) in polycrystalline ferromagnetic (FM) nano-scale thin films, i.e. (001)-oriented cubic films such as Fe, Ni, CFO and (0001)- oriented hexagonal films such as Co, grown on ferroelectric (FE) substrates, for example PZT, BTO substrates. The model of FM/FE bilayered heterostructures has been applied to study the total free energy of the FM films. By minimizing this energy, we have shown that temperature has a significant effect on a critical electric field induced magnetic reorientation. | Communications in Physics, Vol. 24, No. 3S1 (2014), pp. 71-79 DOI:10.15625/0868-3166/24/3S1/5222 THE TEMPERATURE-SENSITIVITY OF A CRITICAL ELECTRIC FIELD INDUCED MAGNETIC EASY-AXIS REORIENTATION FERROMAGNETIC/FERROELECTRIC LAYERED HETEROSTRUCTURES NGUYEN THI MINH HONG Laboratory for Micro and Nanotechnology, University of Engineering and Technology, Vietnam National University, Hanoi PHAM DUC THANG, DANG DINH LONG, PHAM THAI HA, NGUYEN NGOC TRUNG Faculty of Engineering Physics and Nanotechnology, University of Engineering and Technology, Vietnam National University, Hanoi PHAM HONG CONG AND NGUYEN DINH DUC Faculty of Engineering Mechanics and Automation, University of Engineering and Technology, Vietnam National University, Hanoi E-mail: hongntm@vnu.edu.vn Received 04 June 2014 Accepted for publication 24 August 2014 Abstract. We have investigated the effects of temperature on the magnetic easy axis reorientation (EARs) in polycrystalline ferromagnetic (FM) nano-scale thin films, i.e. (001)-oriented cubic films such as Fe, Ni, CFO and (0001)oriented hexagonal films such as Co, grown on ferroelectric (FE) substrates, for example PZT, BTO substrates. The model of FM/FE bilayered heterostructures has been applied to study the total free energy of the FM films. By minimizing this energy, we have shown that temperature has a significant effect on a critical electric field induced magnetic reorientation. Keywords: magnetoelectric effect, multiferroic materials, magnetic reorientation. I. INTRODUCTION The mutiferroic materials have been the subject of intense experimental and theoretical investigations, motivated by the coexistence of at least two ferroic phases that these systems display [1, 2]. In multiferroic materials, the coupling interaction between the different order parameters, indeed, is governed by the magnetoelectric (ME) effect discovered long time ago by Landau and Lifshitz from thermodynamics and symmetry considerations [3]. Interestingly, neither of .