1999 Fiscal Year Annual Research Report

周波数連続掃引が可能なマイクロ波・ミリ波スペクトロメータの開発

Research Project

Project/Area Number	10554015
Research Institution	THE UNIVERSITY OF TOKYO
Principal Investigator	前田京剛東京大学, 大学院・総合文化研究科, 助教授 (70183605)
Co-Investigator(Kenkyū-buntansha)	北野晴久東京大学, 大学院・総合文化研究科, 助手 (00313164) 花栗哲郎東京大学, 大学院・新領域創成科学研究科, 助教授 (40251326)
Keywords	ミリ波 / マイクロ波 / スペクトロメーター / 周波数連続掃引 / 高温超伝導 / ボルテックス / 複素伝導度
Research Abstract	本研究では,マイクロ波・ミリ波領域において周波数掃印が可能な電気伝導度測定システムの構築を目指した。具体的には,(1)導波管内に試料をおき,非共振の状態での測定を行う,あるいは,同軸ケーブルを用いて測定を行う (2)試料に対する電磁場の方向をそろえ,また,電磁場の強度を上げるため,周波数可変なハイブリッド型空洞を用いた共振測定の二つの方法を研究開始時点では計画した。研究が二年目に入り,進捗状況を鑑みて,(1)の方法に的を絞り研究を続けた。研究機関が終了した現時点での成果は以下のとおりである。 (1)1MHz-3GHzまでの,同軸ケーブルを用いた連続周波数スイープ測定システムを完成させた。Referenceの試料で測定を行い,伝導度が正しく得られることを確認した。(2)同システムを用いて,磁場中のBSCCO試料の伝導度測定を行ったが,S/N比が十分でなく,目的のデータ得るに至っていない。今後,ネットワークアナライザーの受信部に増幅器を入れるか,薄膜試料を得ることによって,試料の生抵抗をあげることにより,ベクトル連続周波数掃印による電気伝導度測定の完成を目指す。(3)YBCO試料の複素伝導度を複数の周波数において測定することに成功し,ボルテックスコアの粘性係数を決めることに初めて成功した。これにより,同系のボルテックスコア-は古典的であることが示された。BSCCO系についても同様の測定を行い,広い組成領域にわたり,同様の結論を得た。このことから,高温超伝導体コア-の古典的性格が極めて普遍的であることが示唆された。

Research Products

(20 results)

All Other

All Publications (20 results)

[Publications] T.Tsuboi: "Study of dynamical phase of Bi_2Sr_2CaCu_2O_y by local noise measurement"Physica B. (in press).
[Publications] H.Kitano: "A collective excitation on the slightly hole-doped ladders of Sr_<14>・xCa_xCu_<24>O_<41> in the microwave and millimeter wave regions"Physica B. (in press).
[Publications] T.Hanaguri: "Effect of first-order vortex phase transition on the electronic states of Bi_2Sr_2CaCu_2O_y"J.Low Temp.Phys.. 117. 1405-1409 (1999)
[Publications] A.Maeda: "Site sensitive measurement of local fluctuation of driven vortex density in Bi_2Sr_2CaCu_2O_y"J.Low Temp.Phys.. 117. 1329-1333 (1999)
[Publications] H.Kitano: "Studies of both intralayer and interlayer electrodynamics of Bi_2Sr_2CaCu_2O_y in the superconducting state"J.Low Temp.Phys.. 117. 1241-1245 (1999)
[Publications] A.Maeda: "Dynamics of vortices and quasiparticles in the mixed state of Bi_2Sr_2CaCu_2O_y"Physica C. (in press).
[Publications] A.Maeda: "Field dependence of penetration depth in an electron-doped cuprate superconductor Nd_<2-x>Ce_xCuO_4 with x=0.16"J.Phys.Soc.Jpn.. 68. 594-598 (1999)
[Publications] T.Hanaguri: "Reduction of the superfluid density in the vortes-liquid phase of Bi_2Sr_2CaCu_2O_y"Phys.Rev.Lett.. 82. 1273-1276 (1999)
[Publications] Y.Tsuchiya: "Interlayer phase correlation of the vortex system around at the coupling transition in Bi_2Sr_2CaCu_2O_y containing columnar defects"Phys.Rev.B. 59. 11568-11574 (1999)
[Publications] S.Tajima: "In-plane charge dynamics in La_<1.6-x>Nd_<0.4>Sr_xCuO_4 : Absence of charge gap in the spin/charge ordered state"Euro Phys.Lett.. 47. 715-721 (1999)
[Publications] A.Maeda: "Ac charge dynamics in the meissner state and the vortex state of Bi_2Sr_2CaCu_2O_y"in "Proceedings of the 11th International Symposium on Superconductivity(ISS'98)". 193-198 (1999)
[Publications] R.Inoue: "Microwave and millimerer-wave conductivity of Sr_<14>Cu_<24>O_<41>"in "Proceedings of the 11th International Symposium on Superconductivity(ISS'98)". 121-124 (1999)
[Publications] Y.Tsuchiya: "High-frequency electromagnetic response in the mixed state of YBa_2Cu_3O_y"Physica C. (in press).
[Publications] Y.Togawa: "Conduction noise in Bi_2Sr_2CaCu_2O_y"Physica C. (in press).
[Publications] H.Kitano: "Observation of collective excitation in Sr_<14-x>Ca_xCu_<24>O_<41>"Physica C. (in press).
[Publications] A.Maeda: "Comparative study of thermal conductivity and surface impedance of Bi_2Sr_2CaCu_2O_y in the mixed state"Physica C. (in press).
[Publications] Y.Tsuchiya: "High frequency surface impedance measurement in the mixed state of Bi_2Sr_2CaCu_2O_y"ISS'99 Proc.. (in press).
[Publications] Y.Togawa: "The conduction noise observered in Bi_2Sr_2CaCu_2O_y single crystal"ISS'99 Proc.. (in press).
[Publications] H.Kitano: "Study of highly anisotropic conductivity and penetration depth of Bi_2Sr_2CaCu_2O_y by using a cavity perturbation technique"ISS'99 Proc.. (in press).
[Publications] S.Tajima: "Optical responses of the stripe phase in high-Tc cuprates"Physica C. (in press).

1999 Fiscal Year Annual Research Report

周波数連続掃引が可能なマイクロ波・ミリ波スペクトロメータの開発

Principal Investigator

前田 京剛 東京大学, 大学院・総合文化研究科, 助教授 (70183605)

Research Products

[Publications] T.Tsuboi: "Study of dynamical phase of Bi_2Sr_2CaCu_2O_y by local noise measurement"Physica B. (in press).

[Publications] H.Kitano: "A collective excitation on the slightly hole-doped ladders of Sr_<14>・xCa_xCu_<24>O_<41> in the microwave and millimeter wave regions"Physica B. (in press).

[Publications] T.Hanaguri: "Effect of first-order vortex phase transition on the electronic states of Bi_2Sr_2CaCu_2O_y"J.Low Temp.Phys.. 117. 1405-1409 (1999)

[Publications] A.Maeda: "Site sensitive measurement of local fluctuation of driven vortex density in Bi_2Sr_2CaCu_2O_y"J.Low Temp.Phys.. 117. 1329-1333 (1999)

[Publications] H.Kitano: "Studies of both intralayer and interlayer electrodynamics of Bi_2Sr_2CaCu_2O_y in the superconducting state"J.Low Temp.Phys.. 117. 1241-1245 (1999)

[Publications] A.Maeda: "Dynamics of vortices and quasiparticles in the mixed state of Bi_2Sr_2CaCu_2O_y"Physica C. (in press).

[Publications] A.Maeda: "Field dependence of penetration depth in an electron-doped cuprate superconductor Nd_<2-x>Ce_xCuO_4 with x=0.16"J.Phys.Soc.Jpn.. 68. 594-598 (1999)

[Publications] T.Hanaguri: "Reduction of the superfluid density in the vortes-liquid phase of Bi_2Sr_2CaCu_2O_y"Phys.Rev.Lett.. 82. 1273-1276 (1999)

[Publications] Y.Tsuchiya: "Interlayer phase correlation of the vortex system around at the coupling transition in Bi_2Sr_2CaCu_2O_y containing columnar defects"Phys.Rev.B. 59. 11568-11574 (1999)

[Publications] S.Tajima: "In-plane charge dynamics in La_<1.6-x>Nd_<0.4>Sr_xCuO_4 : Absence of charge gap in the spin/charge ordered state"Euro Phys.Lett.. 47. 715-721 (1999)

[Publications] A.Maeda: "Ac charge dynamics in the meissner state and the vortex state of Bi_2Sr_2CaCu_2O_y"in "Proceedings of the 11th International Symposium on Superconductivity(ISS'98)". 193-198 (1999)

[Publications] R.Inoue: "Microwave and millimerer-wave conductivity of Sr_<14>Cu_<24>O_<41>"in "Proceedings of the 11th International Symposium on Superconductivity(ISS'98)". 121-124 (1999)

[Publications] Y.Tsuchiya: "High-frequency electromagnetic response in the mixed state of YBa_2Cu_3O_y"Physica C. (in press).

[Publications] Y.Togawa: "Conduction noise in Bi_2Sr_2CaCu_2O_y"Physica C. (in press).

[Publications] H.Kitano: "Observation of collective excitation in Sr_<14-x>Ca_xCu_<24>O_<41>"Physica C. (in press).

[Publications] A.Maeda: "Comparative study of thermal conductivity and surface impedance of Bi_2Sr_2CaCu_2O_y in the mixed state"Physica C. (in press).

[Publications] Y.Tsuchiya: "High frequency surface impedance measurement in the mixed state of Bi_2Sr_2CaCu_2O_y"ISS'99 Proc.. (in press).

[Publications] Y.Togawa: "The conduction noise observered in Bi_2Sr_2CaCu_2O_y single crystal"ISS'99 Proc.. (in press).

[Publications] H.Kitano: "Study of highly anisotropic conductivity and penetration depth of Bi_2Sr_2CaCu_2O_y by using a cavity perturbation technique"ISS'99 Proc.. (in press).

[Publications] S.Tajima: "Optical responses of the stripe phase in high-Tc cuprates"Physica C. (in press).

前田京剛東京大学, 大学院・総合文化研究科, 助教授 (70183605)