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Record W4401580006 · doi:10.1016/j.mtnano.2024.100510

Single-crystalline HfO2 nanostructures with novel ferromagnetic properties

2024· article· en· W4401580006 on OpenAlex
Mahdi Beedel, Md. Anisur Rahman, Hanieh Farkhondeh, Joseph P. Thomas, Lei Zhang, Nina F. Heinig, K. T. Leung

Why this work is in the frame

A frame that forgets how it found something cannot be audited. These are the routes that admitted this work.

affAt least one author lists a Canadian institution in the pinned OpenAlex snapshot.
fundA Canadian funder is recorded on the work.

Bibliographic record

VenueMaterials Today Nano · 2024
Typearticle
Languageen
FieldEngineering
TopicSemiconductor materials and devices
Canadian institutionsUniversity of Waterloo
FundersNatural Sciences and Engineering Research Council of Canada
KeywordsFerromagnetismMaterials scienceNanostructureNanotechnologyCondensed matter physicsPhysics

Abstract

fetched live from OpenAlex

Hafnium oxide (HfO 2 ) has special technological significance due to its superior properties such as high dielectric constant (κ∼25), wide bandgap (∼5.7 eV), and superb thermal and chemical stabilities. Its room-temperature ferromagnetism and excellent CMOS technology compatibility make it a promising candidate for seamless CMOS-spintronics integration. Low-dimensional single-crystalline HfO 2 nanostructures, particularly one dimensional (1D) nanostructures, are expected to exhibit enhanced ferromagnetic properties due to large specific surface areas and potentially more surface defects. To date, the synthesis of single-crystalline HfO 2 1D nanostructures has, however, remained elusive. Here, single-crystalline dopant-free HfO 2 nanostructures with notable morphologies, including HfO 2 1D nanostructures, are grown using catalyst-assisted pulsed laser deposition. It is shown that Sn plays a crucial role in producing these 1D nanostructures by increasing both the VLS nucleation and growth rates. Magnetization measurements reveal room-temperature ferromagnetism in HfO 2 nanowires, contrasting with weak paramagnetic responses in HfO 2 nanostructured films. We also provide the first direct evidence of oxygen vacancies as the source of room-temperature ferromagnetism in HfO 2 . To account for the observed magnetic property, we employ a modified bound magnetic polaron-band ferromagnetism hybrid model, which is also generally applicable to dopant-free nanostructures of other metal oxides. This work provides new insights into the growth of novel metal oxide 1D nanostructures and the design of new dilute magnetic semiconducting oxides for potential integrated CMOS-spintronics applications. • This study marks the first successful fabrication of single-crystalline 1D HfO 2 nanostructures. • Sn-Gold Nano Island alloy-catalysts play a crucial role in producing 1D HfO 2 nanostructures. • HfO 2 NWs exhibit novel room-temperature ferromagnetism in contrast to HfO 2 nanostructured films. • Direct evidence for the oxygen-vacancy-induced ferromagnetism in HfO 2 is provided by X-ray photoelectron spectroscopy. • These HfO 2 1D nanostructures hold great promise for integrated CMOS-spintronics applications.

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.

Full frame distilled prediction

Teacher imitation

Not calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.

metaresearch head score (Codex)0.000
metaresearch head score (Gemma)0.000
Version: codex-gemma-dda1882f352aValidation status: machine_predicted_unvalidated
Candidate categoriesInsufficient payload (model declined to judge)
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 score0.022
Threshold uncertainty score1.000

Codex and Gemma teacher scores by category

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 communication0.0010.000
Open science0.0000.000
Research integrity0.0000.000
Insufficient payload (model declined to judge)0.0010.000

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 head0.017
GPT teacher head0.189
Teacher spread0.172 · 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