{"created":"2023-06-19T10:30:05.026021+00:00","id":10238,"links":{},"metadata":{"_buckets":{"deposit":"3f1e0639-8c1a-42df-9ca5-1dbad3835bdb"},"_deposit":{"created_by":18,"id":"10238","owners":[18],"pid":{"revision_id":0,"type":"depid","value":"10238"},"status":"published"},"_oai":{"id":"oai:muroran-it.repo.nii.ac.jp:00010238","sets":["41:227"]},"author_link":["57645"],"item_81_date_granted_17":{"attribute_name":"学位授与年月日","attribute_value_mlt":[{"subitem_dategranted":"2020-03-23"}]},"item_81_degree_grantor_10":{"attribute_name":"学位授与機関","attribute_value_mlt":[{"subitem_degreegrantor":[{"subitem_degreegrantor_language":"ja","subitem_degreegrantor_name":"室蘭工業大学"},{"subitem_degreegrantor_language":"en","subitem_degreegrantor_name":"Muroran Institute of Technology"}],"subitem_degreegrantor_identifier":[{"subitem_degreegrantor_identifier_name":"10103","subitem_degreegrantor_identifier_scheme":"kakenhi"}]}]},"item_81_degree_name_11":{"attribute_name":"学位名","attribute_value_mlt":[{"subitem_degreename":"博士（工学）","subitem_degreename_language":"ja"}]},"item_81_description_25":{"attribute_name":"フォーマット","attribute_value_mlt":[{"subitem_description":"application/pdf","subitem_description_type":"Other"}]},"item_81_description_7":{"attribute_name":"抄録","attribute_value_mlt":[{"subitem_description":"熱電変換材料は，効率的に熱エネルギーを電気エネルギーに直接変換可能な材料であり，熱電発電や熱電冷却に不可欠な電子材料である。熱電変換材料の性能は，性能指数Z＝S2/PK (S：ゼーベック係数，P：電気抵抗率，K：熱伝導率)で評価され，これに絶対温度Tを乗じた無次元性能指数ZT≧1 が実用化の目安となっている。熱伝導率Kは，さらに電子による寄与（KE）と格子による寄与（KL）の和で表される．熱電性能を決定する各パラメータS，P，KEは，いずれもキャリア濃度の関数であり独立に制御することはできない。しかし，格子熱伝導率KLは，結晶構造等で決まり，キャリア濃度に依存しないため，独立に制御可能である。キャリア濃度を最適化した上で，さらにZTを向上させる方法として，KLの低減は重要である。CoSb3は，その特殊な結晶構造・電子構造から，熱電変換材料への応用が期待されている物質であるが，熱伝導率Kが高いことが欠点である。CoSb3に希土類等を部分充填させた化合物は，格子熱伝導率KLが大きく低減することが報告されている。充填率を高めることで，さらに格子熱伝導度を下げることが可能である。高圧合成法は，充填率を高めた試料の合成に有効な手段である。二元系のスクッテルダイト化合物の中で，RhSb3も優れた熱電変換材料の候補である。しかし，RhSb3を基本とした部分充試料の合成および熱電特性評価は，ほとんど行われていない。本研究では， 部分充填スクッテルダイトYbxRh4Sb12の高圧合成を試み，試料評価，熱電特性評価を行った。実際のYbの充填率xの最大値は，0.45であった。この値はこれまでに報告されているYbxRh4Sb12の充填率よりも高い値である。ゼーベック係数，ホール効果の測定から，YbxRh4Sb12は n型伝導体であることがわかった。また，YbxRh4Sb12のZTの最大値は420 Kで0.1程度であったが，出力因子（S2/P）は，広い温度範囲（250 K ～ 450 K）で実用化の目安となる高い値（10-3 Wm-1K-2)を示すことが確認できた。これらの結果は，今後の熱電変換材料の設計の幅を広げることにつながり，次世代の高性能な熱電変換材料開発の発展に寄与するものであると考えられる。","subitem_description_language":"ja","subitem_description_type":"Abstract"},{"subitem_description":"Thermoelectric (TE) materials have been utilized for power generation devices by the direct conversion of waste heat into electrical power. The efficiency of TE materials is determined by the dimensionless figure of merit ZT=S2T/ρκ, where S is the Seebeck coefficient, T is the absolute temperature, ρ is the electrical resistivity, and κ is the thermal conductivity. CoSb3-based skutterudite compounds have attracted considerable attention as one of the best candidates of TE materials. Although CoSb3 shows excellent thermoelectric properties, κ is very high. The reduction in κ for a partially filled CoSb3-based skutterudite is one promising method for improving the TE performance. Partially filled skutterudite compounds with high filling ratio are expected for high-performance TE materials. High pressure benefits the entrance of guest ions into the voids of the filled skutterudite structure than ambient pressure. Among binary skutterudite compounds, RhSb3 is another promising TE materials. However, only a few studies have been conducted on the TE properties of partially guest ion filled RhSb3-based compounds. In this study, we have tried to synthesize partially filled skutterudites YbxRh4Sb12 using a high-pressure and high-temperature (HPHT) synthesis method. The structure and chemical composition of the samples were studied and the actual Yb filling ratios were estimated. The electrical and thermal transport properties were studied for selected compounds. The actual filling ratio x of Yb was estimated by scanning electron microscopy (SEM) with energy-dispersive X-ray spectrometry (EDX). SEM–EDX result indicates that the maximum x values of Yb can be increased to 0.45. This value has been considered to be higher than any YbxRh4Sb12 reported thus far. The electrical resistivity, thermal conductivity, and Seebeck coefficient measurements of the compounds were performed from 2 to 700 K. The Seebeck and Hall coefficients of Yb-filled samples exhibited the n-type conductor behavior. The maximum ZT values of YbxRh4Sb12 were determined to be 0.1 at 420 K. The power factor value is significantly large (more than 10-3 Wm-1K-2) at a wide temperature range between 250 K and 450 K. These results contribute development of next-generation TE materials.","subitem_description_language":"en","subitem_description_type":"Abstract"}]},"item_81_dissertation_number_13":{"attribute_name":"学位授与番号","attribute_value_mlt":[{"subitem_dissertationnumber":"甲第443号"}]},"item_81_identifier_registration":{"attribute_name":"ID登録","attribute_value_mlt":[{"subitem_identifier_reg_text":"10.15118/00010185","subitem_identifier_reg_type":"JaLC"}]},"item_81_subject_9":{"attribute_name":"日本十進分類法","attribute_value_mlt":[{"subitem_subject":"549","subitem_subject_scheme":"NDC"}]},"item_81_text_12":{"attribute_name":"学位の種別","attribute_value_mlt":[{"subitem_text_language":"ja","subitem_text_value":"課程博士"}]},"item_81_text_14":{"attribute_name":"報告番号","attribute_value_mlt":[{"subitem_text_language":"ja","subitem_text_value":"甲第443号"}]},"item_81_text_15":{"attribute_name":"学位記番号","attribute_value_mlt":[{"subitem_text_language":"ja","subitem_text_value":"博甲第443号"}]},"item_81_text_16":{"attribute_name":"研究科・専攻","attribute_value_mlt":[{"subitem_text_language":"ja","subitem_text_value":"工学専攻"}]},"item_81_version_type_24":{"attribute_name":"著者版フラグ","attribute_value_mlt":[{"subitem_version_resource":"http://purl.org/coar/version/c_970fb48d4fbd8a85","subitem_version_type":"VoR"}]},"item_access_right":{"attribute_name":"アクセス権","attribute_value_mlt":[{"subitem_access_right":"open access","subitem_access_right_uri":"http://purl.org/coar/access_right/c_abf2"}]},"item_creator":{"attribute_name":"著者","attribute_type":"creator","attribute_value_mlt":[{"creatorAffiliations":[{"affiliationNameIdentifiers":[],"affiliationNames":[{"affiliationName":""}]}],"creatorNames":[{"creatorName":"SIRIMART, Jirattagan","creatorNameLang":"en"},{"creatorName":"シリマート, ジラッタガン","creatorNameLang":"ja"}],"familyNames":[{},{}],"givenNames":[{},{}],"nameIdentifiers":[{}]}]},"item_files":{"attribute_name":"ファイル情報","attribute_type":"file","attribute_value_mlt":[{"accessrole":"open_date","date":[{"dateType":"Available","dateValue":"2020-06-08"}],"displaytype":"detail","filename":"A443.pdf","filesize":[{"value":"4.4 MB"}],"format":"application/pdf","licensetype":"license_note","mimetype":"application/pdf","url":{"label":"A443","objectType":"fulltext","url":"https://muroran-it.repo.nii.ac.jp/record/10238/files/A443.pdf"},"version_id":"7e6c6879-7717-4781-a4d4-bb33b5accad4"},{"accessrole":"open_date","date":[{"dateType":"Available","dateValue":"2020-06-08"}],"displaytype":"detail","filename":"A443_summary.pdf","filesize":[{"value":"563.7 kB"}],"format":"application/pdf","licensetype":"license_note","mimetype":"application/pdf","url":{"label":"A443_summary","objectType":"abstract","url":"https://muroran-it.repo.nii.ac.jp/record/10238/files/A443_summary.pdf"},"version_id":"c6a1077f-d23b-46b3-bcd6-c2511670a13e"}]},"item_language":{"attribute_name":"言語","attribute_value_mlt":[{"subitem_language":"eng"}]},"item_resource_type":{"attribute_name":"資源タイプ","attribute_value_mlt":[{"resourcetype":"doctoral thesis","resourceuri":"http://purl.org/coar/resource_type/c_db06"}]},"item_title":"High-pressure  synthesis and thermoelectric  properties  of partially  filled skutterudite compounds YbxRh4Sb12","item_titles":{"attribute_name":"タイトル","attribute_value_mlt":[{"subitem_title":"High-pressure  synthesis and thermoelectric  properties  of partially  filled skutterudite compounds YbxRh4Sb12","subitem_title_language":"en"},{"subitem_title":"部分充填スクッテルダイト化合物 YbxRh4Sb12 の高圧合成と熱電特性","subitem_title_language":"ja"}]},"item_type_id":"81","owner":"18","path":["227"],"pubdate":{"attribute_name":"PubDate","attribute_value":"2020-06-08"},"publish_date":"2020-06-08","publish_status":"0","recid":"10238","relation_version_is_last":true,"title":["High-pressure  synthesis and thermoelectric  properties  of partially  filled skutterudite compounds YbxRh4Sb12"],"weko_creator_id":"18","weko_shared_id":-1},"updated":"2024-01-22T01:54:22.843035+00:00"}