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Record W2280524487

Exploring the Design of Multiferroic Materials by Nanocrystal Building Block Approach

2015· dissertation· en· W2280524487 on OpenAlexfundno aff
Penghui Yin

Bibliographic record

VenueUWSpace (University of Waterloo) · 2015
Typedissertation
Languageen
FieldMaterials Science
TopicChemical and Physical Properties of Materials
Canadian institutionsnot available
FundersDivision of Materials ResearchUniversity of Waterloo
KeywordsNanocrystalMultiferroicsBlock (permutation group theory)Materials scienceNanotechnologyEngineering physicsEngineeringOptoelectronicsMathematicsFerroelectricityGeometry
DOInot available

Abstract

fetched live from OpenAlex

Multiferroic materials have been extensively studied as they exhibit both magnetic and electric properties simultaneously, and could be potential candidate materials for the new generation of magnetoelectric (ME) devices. Perovskite materials with room-temperature ferroelectric ordering and simple crystal structure have emerged as favorable building blocks for developing multiferroic devices. In this work, we investigated different approaches to introducing magnetic properties into ferroelectric BaTiO3 and PbTiO3 nanostructures synthesized by hydrothermal method. Specifically, we investigated doping of perovskite nanostructures with magnetic centers as an intrinsic approach, and the formation of nanocomposite with ferrimagnetic
\nspinel Co0.6Fe2.4O4 nanocrystals as an extrinsic approach to multiferroic nanostructures with different morphologies. Investigation of morphology, crystal structure, and magnetic properties of nanoscale perovskite materials and their heterostructures shows promising results towards developing materials which exhibit room-temperature multiferroic properties. Mn-doped BaTiO3 nanoparticles (NPs) were synthesized with different size and doping concentrations. Small particle size and high doping concentration favor the crystal phase transformation from tetragonal to cubic crystal structure. Mn-doped BaTiO3 NPs prepared in ethanol with an average size of ca. 6.4 nm show evidence of tetragonal crystal structure with doping concentration up to 10%. UV-visible absorption spectrum of the colloidal sample indicates the existence of Mn3+ ions in BaTiO3 lattice which is further confirmed by Mn L-edge X-ray absorption spectrum. Additional magnetic and magneto-optical properties measurements could shed light on the single-phase multiferroic nanomaterials. 
\nMultiferroic composites were attempted by incorporating ferroelectric BaTiO3 and ferrimagnetic Co0.6Fe2.4O4 NPs through impregnation or spin coating. Multi-domain structure is observed in high resolution transmission electron microscopy (HRTEM) images of the nanocomposite consisting of BaTiO3 and Co0.6Fe2.4O4 nanostructures. X-ray diffraction and Raman spectroscopy measurements indicate the existence of tetragonality in both type of composites after annealing at 373 K. In addition, magnetic measurements suggest that the composites have enhanced coercivity compared to ferrimagnetic component alone. Transparent multiferroic multilayer
\nstructure was obtained by spin-coating transparent PbTiO3 thin films with Co0.6Fe2.4O4 nanocrystals. This structure provides an opportunity to study the ME coupling between two building blocks with different magneto-optical spectroscopies.

Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.

How this classification was reachedexpand

Full frame machine prediction

Teacher imitation

Not calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.

metaresearch head score (Codex)0.000
metaresearch head score (Gemma)0.000
Version: metacan-v3-hybrid-931329e0061cValidation status: machine_predicted_unvalidated
Candidate categoriesnone
Consensus categoriesnone
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Bench or experimental · Consensus signal: Bench or experimental
GenreCandidate signal: Empirical · Consensus signal: Empirical
Teacher disagreement score0.001
Threshold uncertainty score0.005

Distilled classifier scores by category (both heads)

CategoryCodexGemma
Metaresearch0.0000.000
Meta-epidemiology (narrow)0.0000.000
Meta-epidemiology (broad)0.0000.000
Bibliometrics0.0000.000
Science and technology studies0.0000.000
Scholarly communication0.0000.001
Open science0.0010.000
Research integrity0.0000.000
Insufficient payload (model declined to judge)0.0010.001

Machine scores (provisional)

The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.

Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.

Opus teacher head0.056
GPT teacher head0.216
Teacher spread0.160 · how far apart the two teachers sit on this one work
Validation statusscore_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it

Classification

machine, unvalidated

Machine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.

The models applied no category: nothing in the taxonomy fit this work.
Study designBench or experimental
Domainnot available
GenreEmpirical

How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".

Quick stats

Citations0
Published2015
Admission routes1
Has abstractyes

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