Electrical and magnetic phase transition studies of Fe and Mn co-doped BaTiO 3

Rajan, Soumya; Gazzali, P. M. Mohammed; Chandrasekaran, G.

doi:10.1016/j.jallcom.2015.09.199

Cited by 50 publications

(12 citation statements)

References 40 publications

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“…Figure displays the Raman spectra of BTO, BFTC, and BCTF samples recorded at room temperature. According to the reported research results, the Raman modes detected in the Raman spectra of the tetragonal BTO single crystal ( P 4 mm ) are about 165 cm –1 [A 1 (TO 1 )], 266 cm –1 [A 1 (TO 2 )], 306 cm –1 [B 1 , E(LO, TO)], 516 cm –1 [A 1 (TO 3 )], and 720 cm –1 [A 1 (LO 3 ), E(LO)] modes. , Theoretically, there are no active Raman modes in the cubic phase, confirming the existence of a single tetragonal phase. Raman analysis shows broad bands at around 251 and 520 cm –1 , possibly due to the local disorder associated with the position of the titanium atoms .…”

Section: Resultsmentioning

confidence: 95%

“…Due to the variation of unit cell volume shrinkage, the calculated strain increases by 2.13 when Co 2+ is incorporated into Ba 2+ and Fe 3+ into Ti 4+ . The calculated strain for BTO was 1.27, which agrees well with the value reported by Rajan et al BCTF and BFTC are in the range of a stable perovskite structure, although Fe and Co doping causes structural distortions in the lattice system. The stabilization of the presented compounds was confirmed by Goldschmidt’s tolerance factor t (eq ).…”

Section: Resultsmentioning

confidence: 99%

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Functionality and Activity of Sol–Gel-Prepared Co and Fe co-Doped Lead-Free BTO for Thermo-Optical Applications

et al. 2023

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The BTO, BFTC, and BCTF compounds were synthesized by the sol–gel method. The XRD study revealed the formation of single-phase tetragonal perovskite structures with the space group (P4mm). The crystalline parameters were studied as a function of Fe and Co contents and occupation of Ba and/or Ti sites by Fe and Co in the BTO lattice. It was found that the obtained strain increases when Ba2+ is substituted by Co2+ and Ti4+ by Fe3+. The Raman investigation confirmed the existence of three active modes (B1/E (TO1LO), (E (TO)/A1(TO3), and (A 1(LO)/E (TO), all of which are related to the existence of the tetragonal phase and strongly support the XRD results. The microstructural study showed a clear correlation between the presence of Fe and Co and the grain size distribution. Optical studies revealed the improvement in band gap energy with transition-metal (Fe and Co) co-doped BTO ceramics. The decrease in the band gap is explained by the competing effects of Columbian interactions, microdeformation, and oxygen defects. The results indicate that the presence of Fe and Co dopants enhances the absorption in the BTO ceramic. The dopants demonstrated an effect on thermal conductivity: they decreased the thermal conductivity of BTO, which is in the range of 0.76–2.23 W m–1 K–1 at room temperature and 2.02–0.27 W m–1 K–1 at elevated temperatures. The microstructure of the manufactured materials and the grain size distribution affect the compressive strength.

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Section: Resultsmentioning

confidence: 95%

Section: Resultsmentioning

confidence: 99%

Functionality and Activity of Sol–Gel-Prepared Co and Fe co-Doped Lead-Free BTO for Thermo-Optical Applications

et al. 2023

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“…The rapid decrease in electric permittivity can be explained by the introduction of larger iron ions into the crystal lattice instead of titanium ions with smaller radii. Such modification is connected with the decrease in the space for off centering [ 17 ]. Moreover, the lower valence of Fe +2 in comparison to Ti +4 created an oxygen vacancy leading to a break in the cooperative vibration of the Ti–O chains [ 18 , 19 ].…”

Section: Resultsmentioning

confidence: 99%

Dielectric and Electrical Properties of BLT Ceramics Modified by Fe Ions

et al. 2020

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The solid solution of the perovskite type structure Ba0.996La0.004Ti1−yFeyO3 (BLTF) for varying iron content (y = 0.1−0.4 mol.%) was obtained as a result of a solid state reaction using the conventional method. At room temperature (Tr < TC), the as-received ceramics reveals a single-phase, tetragonal structure and a P4mm space group. An increase in the iron content causes a slight decrease in the volume of the elementary cell. In addition, this admixture significantly reduces the maximum permittivity value (εm) and the shift of the phase transition temperature (TC) towards lower temperatures. The BLTF solid solution shows a classical phase transition and low values of dielectric loss tangent (tgδ), both at room temperature and in the phase transition area. The Curie–Weiss temperature (T0) and Curie constant (C) were also determined on the basis of the dielectric measurements results. The analysis of temperature changes in DC conductivity revealed presence of the positive temperature coefficient of resistivity (PTCR) effect in the phase transition area.

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“…This unique ability to present at least two ferroic order parameters makes multiferroics prime candidates not only for data storage, but also in drug delivery, magnetic field sensing, spintronics, and microwave technology. − Previous studies focused exclusively on BiFeO 3 -based perovskite materials, which exhibit multiferroism at room temperature, but the cross coupling between the two order parameters (magnetization and dielectric polarization) is generally weak. Alternately, other groups suggested that ferroelectric perovskites can be amenable to a magnetic order and exhibit multiferroic properties at room temperature upon the aliovalent doping with transition metal ions. − Son and co-workers reported recently on the design of high-density four-state memories by using arrays of 2% (atom) Mn-doped BaTiO 3 nanorods obtained by dip pen nanolithography. They found that these nanorods exhibit a robust ferroelectric and magnetic response at room temperature with a high electrical fatigue resistance and phase shift of the magnetic signal (up to 10 3 cycles), which shows that transition-metal-doped perovskites are strong candidates for implementation into four-level multiferroic memories .…”

Section: Introductionmentioning

confidence: 99%

Quasi-Monodisperse Transition-Metal-Doped BaTiO₃ (M = Cr, Mn, Fe, Co) Colloidal Nanocrystals with Multiferroic Properties

Costanzo

McCracken

Rotaru

et al. 2018

ACS Appl. Nano Mater.

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The recent demand of multifunctional materials and devices for advanced applications in energy conversion and data storage resulted into a revival of multiferroics, that is, materials characterized by the coexistence of ferromagnetism and ferroelectricity. Despite intense efforts made in the past decade, single-phase room temperature multiferroics are yet to be discovered/fabricated. Nanostructured ferroic materials could potentially exhibit multiferroism since a high fraction of their atoms/ions are superficial, thereby altering significantly the properties of the bulk phase. Alternately, a magnetic order can be induced into ferroelectric materials upon aliovalent doping with magnetic ions. Here, we report on the synthesis of aggregate-free single-phase transition-metal-doped BaTiO3 quasi-monodisperse cuboidal nanocrystals (NC) which exhibit multiferroic properties at room temperature and can be suitable for applications in data storage. The proposed synthetic route allows the inclusion of a high concentration of magnetic ions such as M n+ (M = Cr, Mn, Fe, Co) up to a nominal concentration of 4% without the formation of any secondary phase. The size of the nanocrystals was controlled in a wide range from ∼15 up to ∼70 nm by varying the reaction time from 48 to 144 h. The presence of unpaired electrons and their magnetic ordering have been probed by electron paramagnetic resonance spectroscopy (EPR), and a vibrating sample magnetometer (VSM). Likewise, an acentric structure, associated with the existence of a dielectric polarization, was observed by lattice dynamics analysis and piezoresponse force microscopy (PFM). These results show that high-quality titanium-containing perovskite nanocrystals which display multiferroic properties at room temperature can be fabricated via soft solution-based synthetic routes, and the properties of these materials can be modulated by changing the size of the nanocrystals and the concentration of the dopant thereby opening the door to the design and study of single-phase multiferroic materials.

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Electrical and magnetic phase transition studies of Fe and Mn co-doped BaTiO 3

Cited by 50 publications

References 40 publications

Functionality and Activity of Sol–Gel-Prepared Co and Fe co-Doped Lead-Free BTO for Thermo-Optical Applications

Functionality and Activity of Sol–Gel-Prepared Co and Fe co-Doped Lead-Free BTO for Thermo-Optical Applications

Dielectric and Electrical Properties of BLT Ceramics Modified by Fe Ions

Quasi-Monodisperse Transition-Metal-Doped BaTiO₃ (M = Cr, Mn, Fe, Co) Colloidal Nanocrystals with Multiferroic Properties

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Electrical and magnetic phase transition studies of Fe and Mn co-doped BaTiO 3

Cited by 50 publications

References 40 publications

Functionality and Activity of Sol–Gel-Prepared Co and Fe co-Doped Lead-Free BTO for Thermo-Optical Applications

Functionality and Activity of Sol–Gel-Prepared Co and Fe co-Doped Lead-Free BTO for Thermo-Optical Applications

Dielectric and Electrical Properties of BLT Ceramics Modified by Fe Ions

Quasi-Monodisperse Transition-Metal-Doped BaTiO3 (M = Cr, Mn, Fe, Co) Colloidal Nanocrystals with Multiferroic Properties

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Product

Resources

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Quasi-Monodisperse Transition-Metal-Doped BaTiO₃ (M = Cr, Mn, Fe, Co) Colloidal Nanocrystals with Multiferroic Properties