On the Room Temperature Ferromagnetic and Ferroelectric Properties of Pb(Fe1/2Nb1/2)O3
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We report the origin of room temperature (RT) ferromagnetic and ferroelectric properties of Pb(Fe1/2Nb1/2)O3 (PFN) ceramic sample prepared by modified solid-state reaction synthesis by a single-step method, based on X-ray diffraction (XRD), neutron diffraction (ND), Mössbauer spectroscopy and electron paramagnetic resonance (EPR) spectroscopy results. Formation of single-phase monoclinic PFN ceramic with Cm space group was confirmed by XRD and ND at RT. The morphology studied by scanning electron microscopy (SEM) confirmed uniform microstructure of the sample with average grain size of ∼2 μm. The ND, Mössbauer spectroscopy, M–H loop and EPR studies were carried out to confirm the existence of weak ferromagnetism at RT. A clear opening of hysteresis (M–H) loop is evidenced as the existence of weak ferromagnetism at RT. EPR spectrum clearly shows the ferromagnetism through a good resonance signal. The symmetric EPR line shape with g = 1.9895 observed in PFN sample was identified to be due to Fe 3+ ions. Mössbauer spectroscopy at RT shows superparamagnetic behaviour with presence of Fe in 3 + valence state. Ferroelectric P–E loops on PFN at RT confirm the existing ferroelectric ordering. Our observation is in agreement with literature, and it supports that the origin of ferromagnetism and ferroelectricity is isolated, i.e. from different regions in the sample. Our results do not support the multiferroic nature of PFN at RT.
KeywordsPb(Fe1/2Nb1/2)O3 Neutron diffraction Mössbauer effect Magnetization
The authors (SM and BA) are thankful to UGC DAE CSR Mumbai Center Experimental Facilities and student fellowship in CSR M 159 project. Also, the authors are thankfullto V R Reddy and S K Upadhyay of UGC DAE CSR Indore Center for the ferroelectric (P − E) loop measurement and discussions.
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