14180

12843

كارشناسي ارشد

ماده چگال

اصفهان : دانشگاه صنعتي اصفهان

1397

ده، ۱۷۳ص.: مصور، جدول، نمودار

حميده شاكري پور

هادي سلامتي

داور مدعو: فاطمه داور; داور داخلي: جواد هاشمي فر

1397/09/27

كتابنامه

فيزيك

فيزيك

ID12843

Preparation and investigation of magnetic element Co and non magnetic elements Ca and Sr substitutions in high temperature superconductor Y Ba2 Cu3 O7 Sepideh Pourasad s pourasad@ph iut ac ir June 26 2018 Department of physics Isfahan University of Technology Isfahan 84156 83111 Iran University code IUT 77142Degree M Sc Language FarsiSupervisor Dr H Shakeripourhshakeri@cc iut ac irAbstractSubstitution of different elements in the superconductor compounds is one of the best waysto consider this question Recent experiments have shown that substitution of magnetic el ements such as Fe Co and Ni in Y place in high superconductor Y Ba2 Cu3 O7 Y BCO increases critical temperature In this experiment for the first time to accurate investi gate of increase in critical temperature caused by magnetic ions substitution magnetic ionCo and non magnetic ion Ca were substituted together in Y0 98 x Co0 02 Cax Ba2 Cu3 O7 with 0 Ca 0 015 and non magnetic ions Ca and Sr were separately substituted inY1 x Ca Sr x Ba2 Cu3 O7 with 0 Ca 0 012 and 0 Sr 0 012 All the sampleswere prepared by the conventional solid state reaction XRD data was analyzed by Rietveldrefinment method and shows that there isn t noticeable impurity in samples and all of themhave an orthorhombic structure with pmmm symmetry The AC Magnetic susceptibilityanalysis shows a reduction in critical temperature Tc while the Ca and Sr content increasein all the samples The critical resistance analysis of the samples is in agreement with thesusceptibility results According to SEM analysis results the grain size was increased andconnections between grains were improved At the end we can say that because Ca andSr have radiuses close to Y radius reduction in critical temperature can attribute to holesreduction or non magnetzation of these ions keywords high Tc superconductor magnetic susceptibility electrical resistivity

حميده شاكري پور

هادي سلامتي

داور مدعو: فاطمه داور; داور داخلي: جواد هاشمي فر