{"created":"2023-06-19T10:29:53.487451+00:00","id":9960,"links":{},"metadata":{"_buckets":{"deposit":"773553b7-5cc1-4d6b-91aa-adf86168a313"},"_deposit":{"created_by":18,"id":"9960","owners":[18],"pid":{"revision_id":0,"type":"depid","value":"9960"},"status":"published"},"_oai":{"id":"oai:muroran-it.repo.nii.ac.jp:00009960","sets":["41:227"]},"author_link":["56162"],"item_81_date_granted_17":{"attribute_name":"学位授与年月日","attribute_value_mlt":[{"subitem_dategranted":"2019-03-25"}]},"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":"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. In this study, we have tried to synthesize partially filled skutterudites LaxCo4Sb12, CexCo4Sb12 and NdxCo4Sb12 were prepared by the high-pressure and high-temperature (HPHT) synthesis method. The structure and chemical composition of the samples were studied and the actual La, Ce and Nd filling ratios were estimated. The electrical and thermal transport properties were studied for selected compounds. The actual filling ratio x of La, Ce or Nd was estimated by scanning electron microscopy (SEM) with energy-dispersive X-ray spectrometry (EDX). SEM-EDX results indicate that the maximum x values of La, Ce, and Nd can be increased to 0.28, 0.37 and 0.33, respectively. These values have been considered the highest for any LaxCo4Sb12, CexCo4Sb12, and NdxCo4Sb12 reported thus far. The electrical resistivity, thermal conductivity, and Seebeck coefficient measurements of the compounds were performed from 5 to 760 K. Furthermore, the Hall coefficient and specific heat of the compounds were also measured below 300 K. The Seebeck and Hall coefficients of La-, Ce-, and Nd-filled samples exhibited the n-type conductor behavior. The maximum ZT values of NdxCo4Sb12 were determined to be 0.48 at 700 K. This results contribute development of next-generation TE materials.","subitem_description_language":"ja","subitem_description_type":"Abstract"},{"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，kLが高いことが欠点である。しかし，CoSb3に希土類元素等を部分的に充填することで，kLが大きく低減することが知られており，充填率が高いほどkLの減少率も高くなることが報告されている。本研究では，高温高圧合成法により， 高い充填率の部分充填スクッテルダイト化合物LaxCo4Sb12, CexCo4Sb12, NdxCo4Sb12 の合成を試みた。その結果，純良な試料の合成に成功し，La, Ce，Nd の最大充填率xは，それぞれ 0.28，0.37，0.33となった。 これらの値は，これまでに報告されている常圧下で合成されたLaxCo4Sb12, CexCo4Sb12, NdxCo4Sb12の充填率よりも高い値であった。得られた試料に関して，電気抵抗率，熱伝導率，ゼーベック係数，ホール係数，比熱の測定を行い，熱電特性を評価した。その結果， La, Ce，Ndを充填した試料は，いずれもn型半導体の性質を示した。 また，最大のZT値は，NdxCo4Sb12の700Kにおいて0.48 と高い値を示した。","subitem_description_language":"ja","subitem_description_type":"Abstract"}]},"item_81_dissertation_number_13":{"attribute_name":"学位授与番号","attribute_value_mlt":[{"subitem_dissertationnumber":"甲第435号"}]},"item_81_identifier_registration":{"attribute_name":"ID登録","attribute_value_mlt":[{"subitem_identifier_reg_text":"10.15118/00009908","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435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435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・先端情報電子工学コース"}]},"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":"MONA, Yuttana","creatorNameLang":"en"},{"creatorName":"モナ, ユッタナ","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":"2019-06-25"}],"displaytype":"detail","filename":"A435.pdf","filesize":[{"value":"4.5 MB"}],"format":"application/pdf","licensetype":"license_note","mimetype":"application/pdf","url":{"label":"A435","objectType":"fulltext","url":"https://muroran-it.repo.nii.ac.jp/record/9960/files/A435.pdf"},"version_id":"4308efc4-e223-448e-a5cb-1d67fb234129"},{"accessrole":"open_date","date":[{"dateType":"Available","dateValue":"2019-06-25"}],"displaytype":"detail","filename":"A435_summary.pdf","filesize":[{"value":"366.2 kB"}],"format":"application/pdf","licensetype":"license_note","mimetype":"application/pdf","url":{"label":"A435_summary","objectType":"abstract","url":"https://muroran-it.repo.nii.ac.jp/record/9960/files/A435_summary.pdf"},"version_id":"3d123429-3652-4a1a-8ae4-58ca946a6071"}]},"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":"Thermoelectric properties of partially filled skutterudites RxCo4Sb12 (R = La, Ce, and Nd) synthesized under high pressures","item_titles":{"attribute_name":"タイトル","attribute_value_mlt":[{"subitem_title":"Thermoelectric properties of partially filled skutterudites RxCo4Sb12 (R = La, Ce, and Nd) synthesized under high pressures","subitem_title_language":"en"},{"subitem_title":"高圧下で合成された部分充填スクッテルダイトRxCo4Sb12 (R = La, Ce および Nd) の熱電特性","subitem_title_language":"ja"}]},"item_type_id":"81","owner":"18","path":["227"],"pubdate":{"attribute_name":"PubDate","attribute_value":"2019-06-25"},"publish_date":"2019-06-25","publish_status":"0","recid":"9960","relation_version_is_last":true,"title":["Thermoelectric properties of partially filled skutterudites RxCo4Sb12 (R = La, Ce, and Nd) synthesized under high pressures"],"weko_creator_id":"18","weko_shared_id":-1},"updated":"2024-01-22T02:43:38.984999+00:00"}