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<DIV><FONT face=Arial size=2><FONT face="Times New Roman"
size=3> COLOQUIOS DEL
DEPARTAMENTO DE
FÍSICA<BR>
FCEyN -
UBA<BR><BR>
Charla, café
y galletitas<BR> En
el Aula Federman, 1er piso Pabellón
I.<BR>
Ciudad Universitaria</FONT>
<DIV> </DIV>
<DIV><FONT face=Arial size=2><FONT face="Times New Roman"
size=3>
El próximo jueves 2 de octubre a las 14 hs<FONT face=Arial
size=2> </FONT></FONT></FONT></DIV>
<DIV><SPAN
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style="FONT-SIZE: 22pt; COLOR: black; FONT-FAMILY: Verdana; mso-bidi-font-size: 12.0pt; mso-ansi-language: ES; mso-fareast-font-family: 'Times New Roman'; mso-fareast-language: ES; mso-bidi-language: AR-SA; mso-bidi-font-family: 'Times New Roman'"><SPAN><FONT
face="Times New Roman" size=5><SPAN><SPAN
style="FONT-SIZE: 12pt; FONT-FAMILY: 'Times New Roman'; mso-ansi-language: ES; mso-fareast-font-family: 'Times New Roman'; mso-fareast-language: ES; mso-bidi-language: AR-SA"><FONT
size=6> </DIV>
<DIV>
<P class=MsoBodyText style="MARGIN: 0cm 0cm 0pt"><SPAN lang=IT><FONT
face=Arial><FONT face="Times New Roman"><FONT size=5><SPAN lang=ES-AR
style="FONT-SIZE: 12pt; FONT-FAMILY: 'Times New Roman'; mso-bidi-font-size: 14.0pt; mso-bidi-font-weight: bold; mso-ansi-language: ES-AR; mso-fareast-font-family: 'Times New Roman'; mso-fareast-language: ES; mso-bidi-language: AR-SA"><STRONG><FONT
size=5> Fluctuaciones</FONT> <FONT
size=5>térmicas y límites a la
</FONT></STRONG></SPAN></FONT></FONT></FONT></SPAN></P>
<P class=MsoBodyText style="MARGIN: 0cm 0cm 0pt"><SPAN lang=IT><FONT
face=Arial><FONT face="Times New Roman"><FONT size=5><STRONG><SPAN lang=ES-AR
style="FONT-SIZE: 12pt; FONT-FAMILY: 'Times New Roman'; mso-bidi-font-size: 14.0pt; mso-bidi-font-weight: bold; mso-ansi-language: ES-AR; mso-fareast-font-family: 'Times New Roman'; mso-fareast-language: ES; mso-bidi-language: AR-SA"><FONT
size=5> corriente crítica en
superconductores</FONT></SPAN><BR></STRONG></FONT></FONT></FONT></SPAN><SPAN
lang=IT><FONT
face=Arial><BR></FONT></SPAN></FONT></SPAN></SPAN></FONT></SPAN></SPAN></SPAN></SPAN></FONT></SPAN></SPAN></SPAN></FONT></SPAN></SPAN></SPAN></SPAN></FONT></SPAN></SPAN></SPAN></FONT></SPAN></SPAN></SPAN></SPAN></FONT></SPAN></SPAN></SPAN><SPAN
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class=MquinadeescribirHTML2><SPAN lang=ES-AR
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size=5><SPAN><FONT face="Times New Roman"><SPAN lang=ES-AR><FONT size=3><SPAN
style="mso-spacerun: yes"> <FONT
size=5> Leonardo
Civale<BR></FONT></SPAN></FONT></SPAN></P></DIV>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><SPAN lang=ES-AR><FONT face=Arial
size=2></FONT></SPAN> </P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><SPAN lang=ES-AR><FONT
size=4><SPAN style="mso-spacerun: yes"><SPAN lang=EN-GB
style="FONT-SIZE: 12pt; mso-ansi-language: EN-GB; mso-fareast-font-family: 'MS Mincho'"><FONT
size=3><SPAN lang=EN-US
style="FONT-SIZE: 16pt; FONT-FAMILY: Verdana; mso-bidi-font-size: 12.0pt; mso-ansi-language: EN-US; mso-fareast-font-family: 'Times New Roman'; mso-fareast-language: ES; mso-bidi-language: AR-SA; mso-bidi-font-family: 'Times New Roman'"><FONT
face="Times New Roman"><FONT
size=4>
Superconductivity</FONT> <FONT size=4>Technology
Center</FONT></FONT></SPAN></FONT></SPAN></SPAN></FONT></SPAN></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><SPAN lang=ES-AR><FONT
size=4><SPAN style="mso-spacerun: yes"><SPAN lang=EN-GB
style="FONT-SIZE: 12pt; mso-ansi-language: EN-GB; mso-fareast-font-family: 'MS Mincho'"><FONT
size=3><SPAN lang=EN-US
style="FONT-SIZE: 16pt; FONT-FAMILY: Verdana; mso-bidi-font-size: 12.0pt; mso-ansi-language: EN-US; mso-fareast-font-family: 'Times New Roman'; mso-fareast-language: ES; mso-bidi-language: AR-SA; mso-bidi-font-family: 'Times New Roman'"><FONT
face="Times New Roman"><FONT
size=4>
Los Alamos National
Laboratory</FONT></FONT></SPAN></FONT></SPAN></SPAN></FONT></SPAN><SPAN
lang=ES-AR></P><?xml:namespace prefix = o ns =
"urn:schemas-microsoft-com:office:office" /><o:p></o:p></SPAN>
<DIV></FONT></SPAN></FONT></SPAN></SPAN></SPAN></FONT></SPAN></SPAN></SPAN></FONT></SPAN></FONT></SPAN></SPAN></SPAN></FONT></SPAN></SPAN></SPAN></FONT></SPAN></FONT></SPAN></SPAN></SPAN></FONT></SPAN></SPAN></SPAN><FONT
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face="Times New Roman"
size=3> </FONT></SPAN><FONT
face=Arial size=2><SPAN lang=ES-AR style="mso-ansi-language: ES-AR"><FONT
face="Times New Roman"
size=3>
</FONT></SPAN></DIV>
<DIV>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><SPAN lang=ES-AR
style="mso-ansi-language: ES-AR"></SPAN>-----------------------------------------------------------------------------------------------------------------------------------------------</P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><BR> </P></DIV>
<DIV><FONT face="Times New Roman" size=3>RESUMEN:</FONT></DIV>
<DIV><SPAN style="mso-ansi-language: ES"><O:P><FONT face="Times New Roman"
size=3> </FONT></O:P></SPAN></DIV>
<DIV align=justify><SPAN style="mso-ansi-language: ES"><O:P></O:P></SPAN><SPAN
style="mso-ansi-language: ES"><O:P><SPAN
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style="FONT-SIZE: 18pt; mso-bidi-font-size: 12.0pt"><FONT
face="Times New Roman"><SPAN class=MquinadeescribirHTML2><SPAN lang=ES-AR
style="FONT-SIZE: 10pt; FONT-FAMILY: Arial"><FONT face="Times New Roman"><FONT
face="Century Gothic" color=black><SPAN
style="FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: 'Century Gothic'"><FONT
face="Times New Roman"><SPAN
style="FONT-SIZE: 16pt; COLOR: black; FONT-FAMILY: 'Times New Roman'; mso-bidi-font-size: 12.0pt; mso-ansi-language: ES; mso-fareast-font-family: 'Times New Roman'; mso-fareast-language: ES; mso-bidi-language: AR-SA"><FONT
size=3><SPAN
style="FONT-SIZE: 16pt; COLOR: black; FONT-FAMILY: 'Times New Roman'; mso-bidi-font-size: 12.0pt; mso-ansi-language: ES; mso-fareast-font-family: 'Times New Roman'; mso-fareast-language: ES; mso-bidi-language: AR-SA"><FONT
size=3><SPAN lang=ES-AR style="mso-ansi-language: ES-AR"><SPAN lang=ES-AR
style="FONT-SIZE: 12pt; FONT-FAMILY: 'Times New Roman'; mso-ansi-language: ES-AR; mso-fareast-font-family: 'Times New Roman'; mso-fareast-language: EN-US; mso-bidi-language: AR-SA"><SPAN
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style="FONT-SIZE: 16pt; mso-bidi-font-size: 12.0pt"><FONT size=3><SPAN
lang=ES-AR
style="FONT-SIZE: 16pt; COLOR: black; FONT-FAMILY: 'Times New Roman'; mso-bidi-font-size: 12.0pt; mso-ansi-language: ES-AR; mso-fareast-font-family: 'Times New Roman'; mso-fareast-language: ES; mso-bidi-language: AR-SA"><SPAN
lang=ES-AR
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face="Times New Roman"><SPAN
style="FONT-SIZE: 16pt; mso-bidi-font-size: 12.0pt"><SPAN
style="FONT-SIZE: 16pt; mso-bidi-font-size: 12.0pt"><FONT size=3><SPAN
style="FONT-SIZE: 20pt; mso-bidi-font-size: 12.0pt"><SPAN lang=ES-AR><SPAN
style="mso-ansi-language: ES"><SPAN lang=ES-AR
style="FONT-SIZE: 15pt; FONT-FAMILY: 'Times New Roman'; mso-bidi-font-size: 12.0pt; mso-ansi-language: ES-AR; mso-fareast-font-family: 'Times New Roman'; mso-fareast-language: ES; mso-bidi-language: AR-SA; mso-bidi-font-family: Times-Roman"><FONT
face=Arial size=3>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><SPAN lang=FR
style="FONT-SIZE: 12pt; mso-ansi-language: FR; mso-fareast-font-family: 'MS Mincho'"><SPAN
lang=EN-US
style="FONT-SIZE: 16pt; FONT-FAMILY: 'Times New Roman'; mso-bidi-font-size: 12.0pt; mso-ansi-language: EN-US; mso-fareast-font-family: 'Times New Roman'; mso-fareast-language: ES; mso-bidi-language: AR-SA"><SPAN
lang=IT
style="FONT-SIZE: 15pt; FONT-FAMILY: 'Times New Roman'; mso-bidi-font-size: 12.0pt; mso-ansi-language: IT; mso-fareast-font-family: 'Times New Roman'; mso-fareast-language: ES; mso-bidi-language: AR-SA"><FONT
size=3>El uso tecnológico de los superconductores depende de su capacidad de
transportar corriente eléctrica sin resistencia. Esta notable propiedad deriva
de la presencia de inhomogeneidades en el material que generan una variación
espacial de la energía de los vórtices, impidiendo su movimiento (y la
disipación asociada) mientras no se exceda la <I
style="mso-bidi-font-style: normal">densidad de corriente crítica</I>,
J<SUB>c</SUB>. Cual es la máxima J<SUB>c</SUB> posible es un problema abierto.
En base al conocimiento actual, sería posible lograr J<SUB>c</SUB> igual a la
densidad de desapareamiento J<SUB>0</SUB>, a la cual se destruyen los pares de
Cooper. Sin embargo, después de décadas de intentos estamos aún muy por debajo
de ese límite: la mayor fracción J<SUB>c</SUB>/J<SUB>0</SUB> medida (en films
delgados de YBa<SUB>2</SUB>Cu<SUB>3</SUB>O<SUB>7</SUB>) es ~0.3. Usando este
sistema como modelo, voy a analizar las causas de esta limitación y discutir
ideas para superarla. En particular me enfocaré en el efecto de las
fluctuaciones térmicas, que reducen J<SUB>c</SUB>. Además discutiré la
J<SUB>c</SUB> esperable en nuevos superconductores de alta T<SUB>c</SUB>
que</FONT> <FONT size=3>eventualmente se descubran.</FONT>
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