熔融織構(gòu)YBa-,2-Cu-,3-O-,7-x-塊材的有效釘扎勢(shì).pdf

1、9062二5分類Q￡U密級(jí)霈』￡磊f箍史訾碩士學(xué)位論文熔融織構(gòu)YBa2Cu307x塊材的有效釘扎勢(shì)田翠鋒指導(dǎo)教師：孫愛民副教授申請(qǐng)學(xué)位級(jí)別：碩士專業(yè)名稱：凝聚態(tài)物型研究方向：低溫與超導(dǎo)物理論文答辯日期：學(xué)位授予單位：答辯委員會(huì)主席：評(píng)閱人：二00六年五月兩北師范大學(xué)碩士學(xué)位論文AbstractDuetothehightransitiontemperatureandthequitehighcriticalcurrentdensitythe

2、YBa2Cu301d(YBCOorY123)superconductorcartbeappliedformanypotentialaspects，suchassuperconduccingmagneticsuspension，superconductingmotorandsuperconductingflywheel’rhisdissertationgivesabriefintroductionofthedevelopedhistory

3、andthelatestinvestigationontheeffectivepinningenergyoftheMTGYBCO，andthesignificanceandmaincontentofthisthesis；tellsoftheresearchmaterialstructure，synthesizetechniqueandphysicalproperties；expatiateontheeffectivepinningene

4、rgyoftheM7IGYBCO，analysisanddeterminingofthethreeparameters(theglassyexponent，thecriticalcurrentdensitypinningenergy)ofeffectivepinningpotential(㈨。1Bymagneticrelaxationmethodweobtainedtheglassyexponent』‘(7rII)ofthemeltte

5、xturedYba2Cu307xsampleTheresultshaveasimilarbehaviorcomparedwithonesusingthemethodofmagneticfieldsweep，andarecompatiblewiththemodelofcollectivepinningtheory2Incollectivepinningtheoryeffectivepinningpotential，U叫isakeypara

6、meterindescribingthermallyactivatedfluxmotion，butitisafunctionoftheexponentⅣ，scaleenergyUoandcriticalcurrentdensityJc，underthebaseofGriessen’Sandourgroup’SmethodsofobtainingJcandp，respectivelyDeterminingu0isfltroublesome

7、problemInthispaperweintroducedanewwayofdeterminingpinningenergyUo，thusthecomplexproblemofgettingU哺hasbeensolvedsuccessfully3Accordingtothecollectivepinningmodel，wedeterminethecriticalcurrentdensityJcformelttexturedYBa2Cu

8、307xbulkbyusingmagnetichystersisloops(MHLs)inavibratingsamplemagnetometer(VSM)，andonlyobservethefishtaileffect(peakeffect)atT=77Kand83KFurtherinvestigationshowsthatthefishtaileffectisthecompetitiveresultoftheglassyexpone