Formation of a KNbO3 single crystal using solvothermally synthesized K2-mNb2O6-m/2 pyrochlore phase

Woong Hee Lee; Young Jin Ko; Mir Im; Sang Hyo Kweon; Sung Hoon Cho; Hai Bo Xu; Chong Yun Kang; Sahn Nahm

doi:10.1007/s10832-018-0149-7

Formation of a KNbO₃ single crystal using solvothermally synthesized K_2-mNb₂O_6-m/2 pyrochlore phase

Woong Hee Lee, Young Jin Ko, Mir Im, Sang Hyo Kweon, Sung Hoon Cho, Hai Bo Xu, Chong Yun Kang, Sahn Nahm

Research output: Contribution to journal › Article › peer-review

1 Citation (Scopus)

Abstract

A K_2-mNb₂O_6-m/2 single crystal with a pyrochlore phase formed when the Nb₂O₅ + x mol% KOH specimens with 0.6 ≤ x ≤ 1.2 were solvothermally heated at 230 °C for 24 h. They have an octahedral shape with a size of 100 μm, and the composition of this single crystal is close to K_1.3Nb₂O_5.65. The single-crystal KNbO₃ formed when the single-crystal K_2-mNb₂O_6-m/2 was annealed at a temperature between 600 °C and 800 °C with K₂CO₃ powders. When annealing was conducted at 600 °C (or with a small amount of K₂CO₃), the KNbO₃ single crystal has a rhombohedral structure that is stable at low temperatures (< − 10 °C). The formation of the rhombohedral KNbO₃ structure can be explained by the presence of the K⁺ vacancies in the specimen. The KNbO₃ single crystal with an orthorhombic structure formed when the K_2-mNb₂O_6-m/2 single crystal was annealed at 800 °C with 20 wt% of K₂CO₃.

Original language	English
Pages (from-to)	37-42
Number of pages	6
Journal	Journal of Electroceramics
Volume	41
Issue number	1-4
DOIs	https://doi.org/10.1007/s10832-018-0149-7
Publication status	Published - 2018 Dec 1

Keywords

KNbO
Metal vacancy
Single crystal
Solvothermal synthesis

ASJC Scopus subject areas

Electronic, Optical and Magnetic Materials
Ceramics and Composites
Condensed Matter Physics
Mechanics of Materials
Materials Chemistry
Electrical and Electronic Engineering

Access to Document

10.1007/s10832-018-0149-7

Cite this

@article{273f375353374ee3baa4effd550727b1,

title = "Formation of a KNbO3 single crystal using solvothermally synthesized K2-mNb2O6-m/2 pyrochlore phase",

abstract = "A K2-mNb2O6-m/2 single crystal with a pyrochlore phase formed when the Nb2O5 + x mol% KOH specimens with 0.6 ≤ x ≤ 1.2 were solvothermally heated at 230 °C for 24 h. They have an octahedral shape with a size of 100 μm, and the composition of this single crystal is close to K1.3Nb2O5.65. The single-crystal KNbO3 formed when the single-crystal K2-mNb2O6-m/2 was annealed at a temperature between 600 °C and 800 °C with K2CO3 powders. When annealing was conducted at 600 °C (or with a small amount of K2CO3), the KNbO3 single crystal has a rhombohedral structure that is stable at low temperatures (< − 10 °C). The formation of the rhombohedral KNbO3 structure can be explained by the presence of the K+ vacancies in the specimen. The KNbO3 single crystal with an orthorhombic structure formed when the K2-mNb2O6-m/2 single crystal was annealed at 800 °C with 20 wt% of K2CO3.",

keywords = "KNbO, Metal vacancy, Single crystal, Solvothermal synthesis",

author = "Lee, {Woong Hee} and Ko, {Young Jin} and Mir Im and Kweon, {Sang Hyo} and Cho, {Sung Hoon} and Xu, {Hai Bo} and Kang, {Chong Yun} and Sahn Nahm",

note = "Funding Information: Acknowledgements This work was supported by the Korea Institute of Energy Technology Evaluation and Planning (KETEP) and the Ministry of Trade, Industry & Energy(MOTIE) of the Republic of Korea(No. 20152020104960). The authors also thank the Ku-Kist graduate school program of Korea University. Funding Information: This work was supported by the Korea Institute of Energy Technology Evaluation and Planning (KETEP) and the Ministry of Trade, Industry & Energy(MOTIE) of the Republic of Korea(No. 20152020104960). The authors also thank the Ku-Kist graduate school program of Korea University. Publisher Copyright: {\textcopyright} 2018, Springer Science+Business Media, LLC, part of Springer Nature.",

year = "2018",

month = dec,

day = "1",

doi = "10.1007/s10832-018-0149-7",

language = "English",

volume = "41",

pages = "37--42",

journal = "Journal of Electroceramics",

issn = "1385-3449",

publisher = "Springer Netherlands",

number = "1-4",

}

TY - JOUR

T1 - Formation of a KNbO3 single crystal using solvothermally synthesized K2-mNb2O6-m/2 pyrochlore phase

AU - Lee, Woong Hee

AU - Ko, Young Jin

AU - Im, Mir

AU - Kweon, Sang Hyo

AU - Cho, Sung Hoon

AU - Xu, Hai Bo

AU - Kang, Chong Yun

AU - Nahm, Sahn

N1 - Funding Information: Acknowledgements This work was supported by the Korea Institute of Energy Technology Evaluation and Planning (KETEP) and the Ministry of Trade, Industry & Energy(MOTIE) of the Republic of Korea(No. 20152020104960). The authors also thank the Ku-Kist graduate school program of Korea University. Funding Information: This work was supported by the Korea Institute of Energy Technology Evaluation and Planning (KETEP) and the Ministry of Trade, Industry & Energy(MOTIE) of the Republic of Korea(No. 20152020104960). The authors also thank the Ku-Kist graduate school program of Korea University. Publisher Copyright: © 2018, Springer Science+Business Media, LLC, part of Springer Nature.

PY - 2018/12/1

Y1 - 2018/12/1

N2 - A K2-mNb2O6-m/2 single crystal with a pyrochlore phase formed when the Nb2O5 + x mol% KOH specimens with 0.6 ≤ x ≤ 1.2 were solvothermally heated at 230 °C for 24 h. They have an octahedral shape with a size of 100 μm, and the composition of this single crystal is close to K1.3Nb2O5.65. The single-crystal KNbO3 formed when the single-crystal K2-mNb2O6-m/2 was annealed at a temperature between 600 °C and 800 °C with K2CO3 powders. When annealing was conducted at 600 °C (or with a small amount of K2CO3), the KNbO3 single crystal has a rhombohedral structure that is stable at low temperatures (< − 10 °C). The formation of the rhombohedral KNbO3 structure can be explained by the presence of the K+ vacancies in the specimen. The KNbO3 single crystal with an orthorhombic structure formed when the K2-mNb2O6-m/2 single crystal was annealed at 800 °C with 20 wt% of K2CO3.

AB - A K2-mNb2O6-m/2 single crystal with a pyrochlore phase formed when the Nb2O5 + x mol% KOH specimens with 0.6 ≤ x ≤ 1.2 were solvothermally heated at 230 °C for 24 h. They have an octahedral shape with a size of 100 μm, and the composition of this single crystal is close to K1.3Nb2O5.65. The single-crystal KNbO3 formed when the single-crystal K2-mNb2O6-m/2 was annealed at a temperature between 600 °C and 800 °C with K2CO3 powders. When annealing was conducted at 600 °C (or with a small amount of K2CO3), the KNbO3 single crystal has a rhombohedral structure that is stable at low temperatures (< − 10 °C). The formation of the rhombohedral KNbO3 structure can be explained by the presence of the K+ vacancies in the specimen. The KNbO3 single crystal with an orthorhombic structure formed when the K2-mNb2O6-m/2 single crystal was annealed at 800 °C with 20 wt% of K2CO3.

KW - KNbO

KW - Metal vacancy

KW - Single crystal

KW - Solvothermal synthesis

UR - http://www.scopus.com/inward/record.url?scp=85049585107&partnerID=8YFLogxK

U2 - 10.1007/s10832-018-0149-7

DO - 10.1007/s10832-018-0149-7

M3 - Article

AN - SCOPUS:85049585107

SN - 1385-3449

VL - 41

SP - 37

EP - 42

JO - Journal of Electroceramics

JF - Journal of Electroceramics

IS - 1-4

ER -