High-resolution structure studies and magnetoelectric coupling of relaxor multiferroicPb(Fe0.5Nb0.5)

Abstract

Pb(Fe0.5Nb0.5)O3 (PFN), one of the few relaxor multiferroic systems, has a G-type antiferromagnetic transition at TN = 143 K and a ferroelectric transition at TC = 385 K. By using high-resolution neutron-diffraction experiments and a total scattering technique, we paint a comprehensive picture of the long-and short-range structures of PFN: (i) a clear sign of short-range structural correlation above TC, (ii) no sign of the negative thermal expansion behavior reported in a previous study, and (iii) clearest evidence thus far of magnetoelectric coupling below TN. We conclude that at the heart of the unusual relaxor multiferroic behavior lies the disorder between Fe 3+ and Nb 5+ atoms. We argue that this disorder gives rise to short-range structural correlations arising from O disorder in addition to Pb displacement.

Studies on the high-temperature ferroelectric transition of multiferroic hexagonal manganite RMnO3

“…, F is the Ginzburg-Landau free energy and Q is the displacement amplitude with α 2 = a(T C − T ) and T C being a critical temperature [25]: the dashed line in figure 6(a) is for what is expected of a 2nd order transition. We used the following parameters for the coefficients of the Ginzburg-Landau function: a = 0.000 815, α 4 = −0.156 656, and α 6 = 0.064 452.…”

“…The lines underneath the two peaks in our Figs. 6(a 𝑄 6 , F is the Ginzburg-Landau free energy and Q is the displacement amplitude with α2 = a(TC-T) and TC being a critical temperature [25]: the dashed line in Fig. 6a is for what is expected of a 2 nd order transition.…”

Doping effects on trimerization and magnetoelectric coupling of single crystal multiferroic (Y,Lu)MnO3

“…According to this model, a typical temperature-depend ence of the unit-cell volume can be described [22,30] by the following formula:…”

Characterization of multiferroic PbFe0.5Nb0.5O3 and PbFe0.5Ta0.5O3 ceramics derived from citrate polymeric precursors

“…PFN and PFT undergo similar sequences of both structural and magnetic phase transitions. Two structural phase transitions among the ferroelectric monoclinic M, ferroelectric tetragonal T, and paraelectric cubic C phases are detected at 355 and 376 K for PFN, and at 220 and 270 K for PF, respectively. It is worth noting here that in the cubic phase up to approximately T C + 60 K, there is a deviation from the linear character of thermal expansion .…”