Engineered Biferroic 0.7Pb(Mg 1/3 Nb 2/3 )O 3 -0.3PbTiO 3 /La 0.6 Sr 0.4 MnO 3 Epitaxial Superlattices
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1034-K03-37
Engineered Biferroic 0.7Pb(Mg1/3Nb2/3)O3-0.3PbTiO3/La0.6Sr0.4MnO3 Epitaxial Superlattices Ayan Roy Chaudhuri, and S.B. Krupanidhi Materials Research Centre, Indian Institute of Science, Sir C.V. Raman Avenue, Bangalore, 560012, India ABSTRACT Symmetric and asymmetric superlattices (SLs) composed of ferromagnetic La0.6Sr0.4MnO3 (LSMO) and ferroelectric 0.7Pb(Mg1/3Nb2/3)O3 – 0.3PbTiO3 (PMN-PT) with different periodicities have been fabricated on LaNiO3 (LNO) coated LaAlO3 (100) (LAO) substrates by pulsed laser ablation deposition. Structural, ferromagnetic and ferroelectric properties have been studied for all the SLs. All the heterostructures exhibited good ferromagnetic response over a wide range of temperatures (10K – 300K), whereas only the asymmetric SLs exhibited reasonably good ferroelectric behaviour. Ferromagnetic and ferroelectric hysteresis loops observed in the asymmetric SLs confirmed their biferroic nature. Studies were conducted towards understanding the influence of LSMO layers on the electrical responses of the heterostructures. Absence of ferroelectricity in the symmetric SL structures has been attributed to their high leakage characteristics. Strong influence of an applied magnetic field of 1.2T was observed on the ferroelectric properties of the asymmetric SLs. The effect of magnetic field on the ferroelectric properties of the SLs indicated possibility of strong interfacial effect. INTRODUCTION Coexistence of ferromagnetism and ferroelectricity in a material, and the coupling between them has attracted renewed importance due to both fundamental and technological interest. Control of ferroelectric polarization by magnetic field and vice versa can effect in designing novel devices with parametric values and flexibility. But the scarcity of intrinsic multiferroic materials and very small magnetoelectric coupling observed in them limit their possibility to be useful in any device application. To address these issues and in search of alternative multiferroic materials there is an upsurge of interest to fabricate artificial heterostructures consisting alternative layers of different ferromagnetic (FM) and ferroelectric (FE) materials [1-3]. In these artificial heterostructures the magnetoelectric coupling between the parent FE (which is also piezoelectric) and a FM (if it is also magnetostrictive) materials can be mediated by elastic strain. In the present study a series of epitaxial Superlattices (SLs) composed of FM LSMO and FE PMN-PT have been fabricated on (100) oriented LAO substrate using pulsed laser ablation. Electrostrictive PMN - PT with a very high piezoelectric coefficient (~1200pC/N) compared to other FE materials like Pb(Zr, Ti)O3, BT, BST etc., might give rise to large strain mediated room temperature (RT) magnetoelectric coupling with magnetostrictive LSMO. Two sets of SLs with four different periodicities (Λ = 6nm, 9nm, 13nm, and 16nm) were fabricated with constant total thickness of the heterostructures. Symmetric SLs were consisted of equal thickness of PMN-PT and LSMO, w
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