YBCO süperiletken örneklerin tüp metodu (PITM) ile hazırlanması, Cd ve Ga katkılanmasının sistem üzerine etkileri
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Dosyalar
Tarih
2003
Yazarlar
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
İnönü Üniversitesi
Erişim Hakkı
info:eu-repo/semantics/openAccess
Özet
Bu çalışmada, YıBa2Cıi307-8 ve Yo.5Xo.5Ba2Cu307.s (X=Ga, Cd ) bileşiğinin Powder-In-Tube metodu ile sentezi ve yeni sistemin elektriksel ve fiziksel özelliklerinin değişmi incelenmiştir. Kimyasal formülleri verilmiş olan bileşikler bir araya getirilerek homojen ve çok küçük parçacık boyutuna sahip olacak şekilde iyice karıştırılmıştır. Hazırlanmış olan ham bileşim 970°C de kalsinasyon işlemine tabi tutulmuştur. Kalsinasyon işlemi esnasında toz halindeki numuneye 500°C sıcaklığa, ulaşıldığında oksijen gazı verildi. Powder-In-Tube metodu kullanılarak 30 mm uzunlukta ve 5 mm yarıçapa sahip Ag tüplerin içerisine hazırlanmış olan kimyasal bileşikler yerleştirildi. Hazırlanmış olan numunelerin tamamı oksijen ortamında ısıl işleme tabi tutulmuştur. 3, 5, 9 ton basınç altında hazırlanmış olan YıBa2Cu3Û7^, Yo.5Cdo.sBa2Cu307-8 ve Yo 5Gao.5Ba2Cu30"7.8 numunelerinin x-ışını kırınım desenleri, direnç ölçümleri, SEM ve EDAX analizi ölçümleri yapılmıştır. X-ışını kırınım sonuçlarında, YıBa2Cu3C«7.s kompozisyonunda hazırlanan numunelerin karakteristik YBCO piklerine oldukça şiddetli ve belirgin bir şekilde sahip olduğu ve bunun sonucunda numunelerin yüksek saflığa sahip olduğu anlaşılmıştır. Uygulanan basıncın etkisi ile pik şiddetlerinde belirgin bir azalma gözlenmiştir. Yo.5Cdo.5Ba2Cu307-s kompozisyonunda ise, YBCO sisteminden farklı olarak değişik konumlarda piklerin yapıda mevcut olduğu görülmüştür. Cd katkısının Y|Ba2Cu307.s yapısını çok fazlı bir sisteme taşıdığı ve süperiletkenlik durumunu olumsuz yönde etkilediği gözlenmiştir. Y0,5Ga0,5Ba2CıuO7-8 kompozisyonunda ise, Ga katkısının süperiletken fazlar üzerinde tamamen olumsuz bir etki meydana getirdiği ve süperiletkenlik durumunu ortadan kaldırdığı anlaşılmıştır. Direnç ölçüm sonuçlarında, YıBa2Cu307-s numunelerinin farklı manyetik alanlar altında direnç ölçümleri alınmış ve yapının çok kaliteli ve homojen olduğu anlaşılmıştır. Bu sistem için süperiletkenlik geçiş sıcaklığı (Tc) 93 K olarak bulunmuştur. Cd ve Ga katkılanarak hazırlanmış olan numunelerde ise, Ga katkısının yapıyı tamamen süperiletken özellikten uzaklaştırdığı görülmüştür. Bunun yanında Cd katkısının Ga katkısına oranla sistem üzerinde daha olumlu sonuçlar verdiği görülmüştür. Cd katkılanması sonucunda numunelerin geçiş sıcaklıkları 85-90 K arasında değiştiği gözlenmiştir. SEM ve EDAX analizi sonuçlarında ise, YıBa2Cu307-5 kompozisyonu için klasik YBCO sisteminin granüler formasyonu ve kısmi olarak erimiş klasik yapılanma çok açık bir şekilde ortaya çıkmıştır. EDAX analizi sonuçlarında, yapının oldukça kaliteli ve homojen olduğu anlaşılmıştır. Cd katkılı numunelerin SEM sonuçlarına göre, numunelerin yüzeyindeki kısmi erimenin YBCO sistemine göre çok daha fazla olduğu ve yarı erimiş bölgeler arasında çok geniş boşlukların bulunduğu gözlenmiştir. Bu sistemin EDAX analizi sonuçlarında ise, YBCO sistemine göre elektriksel özelliklerin olumsuz yönde etkilendiği anlaşılmıştır. Ga katkılı numunelerin SEM sonuçlarına göre, Cd katkılanan sisteme oranla olumsuz sonuçlar elde edilmiştir. Yapıda yaklaşık aynı büyüklükte farklı geometrik şekillerde tam granüler (erimemiş) yapılaşma oluşmasından dolayı süperiletkenlik gözlenmemiştir. Bu sistemin EDAX analizi sonuçlarında ise, yapı içerisindeki bakırın farklı bölgelerde öbekler halinde reaksiyona girmeden kalabileceği sonucuna ulaşılmıştır. ANAHTAR KELİMELER: Powder-In-Tube (PIT) metodu, YBCO, Katıhal-reaksiyon yöntemi
In this study, YiBa2Cu307.s and Y0.5Xo.5Ba2Cu307.g (X=Ga, Cd) compounds were synthesied by Powder-In-Tube method and electrical and physical properties of system were investigated. After getting together the compounds that chemical formulas are given, they were mixed in order to have homogen and small granular size. This raw compound was calcinated to 970 °C. While the calcination process, oxygen gas was given to powder sample at 500 °C. Chemical compounds were put into 30 mm lenght and 5 mm diameter Ag tubes. All of the obtained samples were heated in oxygen atmosphere. YiBa2Cu307.5, Yo.5Cdo.5Ba2Cu307-8 and Yo.sGao.sBaaC^Ov-s samples were prepared under 3, 5, 9 tons and X-ray difractions, electical resistance, SEM and EDAX, analysis measurements were done. In the results of X-ray difraction, it is seen that samples which are prepared from YiBa2Cu307"g composition exhibit quite clear characteristic of YBCO peaks and as a conccqucncc of this, samples have high purity. Decrease in magnitude of peaks by effect of applied pressure was observed. In the Yo.sCdo.sBaaCu-sO?^ composition, peaks in which reside in different positions from those of YBCO system were seen in the structure. It was observed that Cd substitution into YıBaaCıijOy-ö, Y|Ba2Cıi307-s structures to multi-phase system and effect its superconductivity state worse. In the Yo.5Gao.5Ba2Cu307-8 composition, it was understood that Ga substitution in Yo.5Gao.5Ba2Cu307_s caused negative effects on superconductor phases and terminated its superconductivity state. In the result of resistance measurements, rcsirtancc of Y1Ba2C1i3O7.fi samples were maeasured under various magnetic field and it was understood that YıBa2Cıi307-s structure was in quite good quality and homogen. Superconductivity transition temperature (Tc) of this system was found to be 93 K. For the Cd and Ga substitution samples, it was seen that Ga substitution led structure entirely lose its superconductivity property. Beside that, it was seen that Cd substitution produced better results on the system than those of Ga substitution. After Cd dopping, it was observed that superconducting transition temperature varied in the range 85-90K. In the result of SEM and EDAX analysis, granular formation of classical YBCO and partial melted classical structuring were seen for YiBa2Cu307_5 composition. In the result of EDAX analysis, it was understood that the structure was in good quality and quite homogen. According to SEM results of Cd substitution samples, it was observed that partial melting on the surface of the samples was much more than that of the YBCO system and there existed very wide gaps between half melted areas. In the results of EDAX analysis of this system, it was understood that electrical properties were badly effected respect to YBCO system. According to SEM results of Ga substitution samples, worse results than those of Cd substitution system were obtained. Superconductivity was vanished in structure. Hence, complete granular structuring in approximiatly the same volume and different shape was took place in the structure. In the result of EDAX analysis of his system, it was concluted that Cu could locally remain in various areas without reacting any material. KEYWORDS: Powder-In-Tune method, YBCO, solid-state reaction method
In this study, YiBa2Cu307.s and Y0.5Xo.5Ba2Cu307.g (X=Ga, Cd) compounds were synthesied by Powder-In-Tube method and electrical and physical properties of system were investigated. After getting together the compounds that chemical formulas are given, they were mixed in order to have homogen and small granular size. This raw compound was calcinated to 970 °C. While the calcination process, oxygen gas was given to powder sample at 500 °C. Chemical compounds were put into 30 mm lenght and 5 mm diameter Ag tubes. All of the obtained samples were heated in oxygen atmosphere. YiBa2Cu307.5, Yo.5Cdo.5Ba2Cu307-8 and Yo.sGao.sBaaC^Ov-s samples were prepared under 3, 5, 9 tons and X-ray difractions, electical resistance, SEM and EDAX, analysis measurements were done. In the results of X-ray difraction, it is seen that samples which are prepared from YiBa2Cu307"g composition exhibit quite clear characteristic of YBCO peaks and as a conccqucncc of this, samples have high purity. Decrease in magnitude of peaks by effect of applied pressure was observed. In the Yo.sCdo.sBaaCu-sO?^ composition, peaks in which reside in different positions from those of YBCO system were seen in the structure. It was observed that Cd substitution into YıBaaCıijOy-ö, Y|Ba2Cıi307-s structures to multi-phase system and effect its superconductivity state worse. In the Yo.5Gao.5Ba2Cu307-8 composition, it was understood that Ga substitution in Yo.5Gao.5Ba2Cu307_s caused negative effects on superconductor phases and terminated its superconductivity state. In the result of resistance measurements, rcsirtancc of Y1Ba2C1i3O7.fi samples were maeasured under various magnetic field and it was understood that YıBa2Cıi307-s structure was in quite good quality and homogen. Superconductivity transition temperature (Tc) of this system was found to be 93 K. For the Cd and Ga substitution samples, it was seen that Ga substitution led structure entirely lose its superconductivity property. Beside that, it was seen that Cd substitution produced better results on the system than those of Ga substitution. After Cd dopping, it was observed that superconducting transition temperature varied in the range 85-90K. In the result of SEM and EDAX analysis, granular formation of classical YBCO and partial melted classical structuring were seen for YiBa2Cu307_5 composition. In the result of EDAX analysis, it was understood that the structure was in good quality and quite homogen. According to SEM results of Cd substitution samples, it was observed that partial melting on the surface of the samples was much more than that of the YBCO system and there existed very wide gaps between half melted areas. In the results of EDAX analysis of this system, it was understood that electrical properties were badly effected respect to YBCO system. According to SEM results of Ga substitution samples, worse results than those of Cd substitution system were obtained. Superconductivity was vanished in structure. Hence, complete granular structuring in approximiatly the same volume and different shape was took place in the structure. In the result of EDAX analysis of his system, it was concluted that Cu could locally remain in various areas without reacting any material. KEYWORDS: Powder-In-Tune method, YBCO, solid-state reaction method
Açıklama
Anahtar Kelimeler
Fizik ve Fizik Mühendisliği, Physics and Physics Engineering
Kaynak
WoS Q Değeri
Scopus Q Değeri
Cilt
Sayı
Künye
Alagöz, S. (2003). YBCO süperiletken örneklerin tüp metodu (PITM) ile hazırlanması, Cd ve Ga katkılanmasının sistem üzerine etkileri. Yayımlanmış Yüksek lisans Tezi, İnönü Üniversitesi, Malatya.
