Ferroelectricity and magnetism in Pb(Fe_0.5Nb_0.5)O₃–Pb(Yb_0.5Nb_0.5)O₃–PbTiO₃ single crystals

Abstract

Domain structure, ferroelectric and magnetic properties of [001]-oriented multiferroic single crystals Pb ( Fe 0.5 Nb 0.5 ) O 3 – Pb ( Yb 0.5 Nb 0.5 ) O 3 – PbTiO 3 (PFN–PYN–PT) with various compositions were investigated with the purpose of understanding the ferroelectric and magnetic order. The samples were determined to be rhombohedral phase or coexistence of tetragonal and rhombohedral phases by means of X-ray diffraction analysis and optical study. Furthermore, the domain configuration in tetragonal phase always takes on 90° domain wall. All samples exhibit well-developed saturated hysteresis loop, indicating no substantial increase of conductivity despite the introduction of Fe 3+ ions. But the piezoelectric coefficients were reduced due to the introduction of PFN. In addition, the PFN–PYN–PT single crystals showed paramagnetic behavior, resulting from the – O – Fe 3+ – O – Nb / Yb / Ti – O – Fe 3+ – O – magnetic interaction. Interestingly, M–H hysteresis loops display a magnetic relaxor behavior.