Composition dependent room temperature structure, electric and magnetic properties in magnetoelectric Pb(Fe 1/2 Nb 1/2 )O 3 Pb(Fe 2/3 W 1/3 )O 3 solid-solutions

Matteppanavar, Shidaling; Rayaprol, Sudhindra; Angadi, Basavaraj; Sahoo, Balaram

doi:10.1016/j.jallcom.2016.03.260

Cited by 30 publications

(6 citation statements)

References 55 publications

(38 reference statements)

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“…30,70−72 Other discontinuous transitions are observed between insulator/conductor or para-/ferromagnetic states. 73 Here it must be stressed that the existence of different crystal forms as a consequence of varied composition cannot be regarded as polymorphism. In fact these phases would not lead to an identical liquid or vapor state.…”

Section: ■ Solid Solutions In Crystal Engineeringmentioning

confidence: 99%

Engineering Crystal Properties through Solid Solutions

Lusi

2018

Crystal Growth & Design

123

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The control of structures and properties in crystalline materials has many returns that justify the increasing efforts in this direction. Traditionally, crystal engineering focused on the rational design of single component molecular crystals or supramolecular compounds (i.e., cocrystals). More recently, reports on crystalline solid solutions have become common in crystal engineering research. Crystalline solid solutions are characterized by a structural disorder that enables the variation of stoichiometry in continuum. Often such variation corresponds to a variation of structural and physicochemical properties, and offers an opportunity for the materials’ fine-tuning. In some cases, though, new and unexpected properties emerge. As illustrated here, both behaviors make solid solutions particularly relevant to the scope of crystal engineering.

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Section: ■ Solid Solutions In Crystal Engineeringmentioning

confidence: 99%

Engineering Crystal Properties through Solid Solutions

Lusi

2018

Crystal Growth & Design

123

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“…This is not surprising given that there are smaller differences in size between Fe 3+ (0.645 A) and W 6+ (0.6 A). The cation ordering in PFWO can be enhanced by both thermal treatment (thermal annealing and quenching) and cation substitution [37][38][39][40][41][42][43][44][45][46][47][48] . In Ref.…”

Section: Discussionmentioning

confidence: 99%

“…It was observed also that the ordering degree in PFWO is hardly modified by annealing treatments, but is very sensitive to doping [28][29][30][31][32][33][34][35][36] . Investigations of the effects of different additives on the order in the PFWO-based ceramics demonstrated that relatively small alterations in the chemistry can produce very large changes in the thermodynamic stability of the ordered structure and induce significant modifications in the magnetic behavior and dielectric/ferroelectric properties, for example, the influences of the Na, Mg, Ti, Zr, Sc, and Yb dopings [37][38][39][40][41][42][43][44][45][46][47][48] . Small amounts of Na, Sc and Yb cation substitutions promote a transformation to an ordered cubic (Fm − 3m) structure.…”

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confidence: 99%

Structure of Pb(Fe2/3W1/3)O3 single crystals with partial cation order

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Riekehr

et al. 2020

Sci Rep

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Despite intensive studies on the complex perovskite Pb(Fe 2/3 W 1/3)o 3 (PFWO) relaxor, understanding the exact nature of its multifunctional properties has remained a challenge for decades. in this work we report a comprehensive structural study of the PFWO single crystals using a combination of synchrotron X-ray diffraction and high-resolution electron microscopy. The set of {h + ½, k + ½, l + ½} superlattice reflections was observed for the first time based on single-crystal synchrotron X-ray experiments (100-450 K) and transmission electron microscopy investigations, which indicates some kind of B-cation ordering in PFWO which had been thought to be totally disordered. It was found that (1) the crystal structure of PFWO should be described by a partly ordered cubic perovskite (i.e. Fm − 3m), (2) the weak ferromagnetic properties and excess magnetic moment of PFWO can be understood based on non-random distribution of Fe cations between the 4a and 4b sites, and (3) the pb displacement disorder is present in this material and the cations are probably displaced along the <100> directions. The X-ray diffraction results of this investigation show that partial cation ordering indeed exists in PFWO, which makes it necessary to revisit the generally accepted interpretations of the results obtained up to date. In agreement with X-ray diffraction study the main results of TEM study include: (1) a long range order that can be described with the Fm − 3m symmetry is reliably detected, (2) the coherence length of that long range order is in the order of 1-2 nm and (3) no remarkable chemical inhomogeneity is found in the tested PFWO crystal, excluding the possibility of a compositional ordering arising from substitutional defects in the perovskite structure. Pb(Fe 2/3 W 1/3)O 3 (PFWO) belongs to the family of Pb-based multiferroic relaxor ferroelectric complex perovskites (AB ′ 1−x B ′′ x O 3) 1-3. PFWO is formed from simple perovskite ABO 3 with the magnetic ions Fe 3+ (3d 5 , S = 5/2) and the non-magnetic ions W 6+ (5d 0 , S = 0) sharing the B-site of the perovskite-type structure. It is generally accepted that this material exhibits a disordered perovskite structure, where Fe 3+ and W 6+ ions are randomly distributed at the centers of the BO 6 octahedra 4-6. PFWO has been the subject of numerous studies due to its attractive combination of spin and dipole orderings 7-10. An interesting feature of PFWO is associated with the presence of magnetic ions Fe 3+ with a relatively high occupancy of 2/3 on the B-octahedral sites, leading to one of highest magnetic ordering temperatures established in multiferroics materials 6 , with the para-to antiferromagnetic transition occurring around T N = 340-380 K 11-14 , where the magnetic ordering is due to the superexchange interaction between the Fe ions through the O ions. Also, this material is a relaxor ferroelectric with a broad and frequency-dependent dielectric maximum (also called diffuse phase transition) around T max (or T C) = 150-200 K 15,16. Despite the 60-year history of P...

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“…Multiferroic materials show at the same phase two spontaneous orderings e.g., ferroelectric and magnetic [3]. There are many ferroelectromagnetic ceramic materials in this group, with interesting properties wherein lead-based materials also dominate, e.g., Pb(Fe 1/2 Nb 1/2 )O 3 [4][5][6], Pb(Fe 2/3 W 1/3 )O 3 [7], Pb(Fe 1/2 Ta 1/2 )O 3 [8], or a combination of them [9]. Lead is connected to unfavorable technological factors-i.e., the formation of lead vacancies (during sintering at high temperatures) and the distorting stoichiometry or crystallographic structure of a compound-as well as harmful and adverse effects of lead on the environment and health human.…”

Section: Introductionmentioning

confidence: 99%

Mechanochemical Activation and Spark Plasma Sintering of the Lead-Free Ba(Fe1/2Nb1/2)O3 Ceramics

et al. 2021

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This paper investigates the impact of the technological process (Mechanochemical Activation (MA) of the powder in combination with the Spark Plasma Sintering (SPS) method) on the final properties of lead-free Ba(Fe1/2Nb1/2)O3 (BFN) ceramic materials. The BFN powders were obtained for different MA duration times (x from 10 to 100 h). The mechanically activated BFN powders were used in the technological process of the BFN ceramics by the SPS method. The measurements of the BFNxMA ceramic samples included the following analysis: Scanning Electron Microscopy (SEM), Energy Dispersive Spectrometry (EDS), DC electrical conductivity, and dielectric properties. X-ray diffractions (XRD) tests showed the appearance of the perovskite phase of BFN powders after 10 h of milling time. The longer milling time (up 20 h) causes the amount of the perovskite phase to gradually increase, and the diffraction peaks are more clearly visible. Short high energy milling times favor a large heterogeneity of the grain shape and size. Increasing the MA milling time to 40 h significantly improves the microstructure of BFN ceramics sintered in the SPS technology. The microstructure becomes fine-grained with clearly visible grain boundaries and higher grain size uniformity. Temperature measurements of the BFN ceramics show a number of interesting dielectric properties, i.e., high values of electric permittivity, relaxation properties with a diffusion phase transition, as well as negative values of dielectric properties occurring at high temperatures. The high electric permittivity values predestines the BFNxMA materials for energy storage applications e.g., high energy density batteries, while the negative values of dielectric properties can be used for shield elements against the electromagnetic radiation.

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Composition dependent room temperature structure, electric and magnetic properties in magnetoelectric Pb(Fe 1/2 Nb 1/2 )O 3 Pb(Fe 2/3 W 1/3 )O 3 solid-solutions

Cited by 30 publications

References 55 publications

Engineering Crystal Properties through Solid Solutions

Engineering Crystal Properties through Solid Solutions

Structure of Pb(Fe2/3W1/3)O3 single crystals with partial cation order

Mechanochemical Activation and Spark Plasma Sintering of the Lead-Free Ba(Fe1/2Nb1/2)O3 Ceramics

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