Improving the multicaloric properties of Pb(Fe0.5Nb0.5)O3 by controlling the sintering conditions and doping with manganese

Strengthened relaxor behavior in (1−x)Pb(Fe0.5Nb0.5)O3–xBiFeO3

“…This synthesis route has proven useful for the preparation of complex single-phase ceramics due to the better chemical homogeneity and partial amorphization of mechanochemically-activated powder, which can lead to lower sintering temperatures and more homogeneous and stoichiometric ceramics. 11,29,30 We show in this study that PFN-100xBFO (x r 0.5) is an interesting system exhibiting relaxor-like behavior. Electrical properties of ferroelectrics and relaxors are strongly dependent on the grain size of the material.…”

“…The preparation process of pure Pb(Fe 0.5 Nb 0.5 )O 3 (PFN) powder is described in our previous work. 11 Prior to the preparation of BFO-containing compositions, all starting oxides were pre-milled in absolute ethanol using a planetary ball mill (Retsch PM400, Retsch, Haan, Germany) at 200 min À1 for 4-6 h or an attrition mill (Netzsch, PE075/PR01, Selb, Germany) at 500 min À1 for 6-8 h. In all cases, yttria-stabilized zirconia (YSZ) milling balls with a diameter of 3 mm were used. All stoichiometric mixtures of starting oxides (40 g) were homogenized in a planetary ball mill at 200 min À1 for 4 h in absolute ethanol using YSZ milling balls (ball diameters 3 mm).…”

“…33 and used in our previous work. 11 The use of saturated oxygen atmosphere during the sintering prevents (or minimizes) the reduction of Fe 3+ to Fe 2+ and reduces the amount of oxygen vacancies, which consequently resulted in a lower electrical conductivity and dielectric losses of the material. 33 For all samples, heating and cooling rates of 2 1C min À1 were used.…”

“…4,6 According to the literature reports, there is still a debate about whether PFN exhibits more ferroelectric-like or relaxor-like behavior. 4,[7][8][9] At room temperature, it exhibits a monoclinic symmetry with Cm space group 10 exhibiting ferroelectric-like P-E hysteresis loops 11 and sub-micron-sized ferroelectric domains. 8,10 It possesses frequency independent (or only slightly dependent, i.e., AE1 1C) peak-permittivity temperature for frequencies below 1 MHz.…”

“…8,10 It possesses frequency independent (or only slightly dependent, i.e., AE1 1C) peak-permittivity temperature for frequencies below 1 MHz. 11,12 However, it was shown 12 that the peak-permittivity temperature becomes frequency dependent in the microwave frequency region (GHz), indicating partial relaxor-like behavior. On the other hand, BFO shows ferroelectric behavior at room temperature and is also considered a high-temperature piezoelectric material due to its extremely high T C .…”