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<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>Vabim vas na 13. predavanje iz sklopa "Kolokviji na IJS" v
letu 2008/09, v okviru Stefanovih dnevov, ki bo <strong><b><font color=red
face="Times New Roman"><span style='color:red'>v četrtek, 26. marca 2009, ob
13:00 uri </span></font></b></strong><font color=red><span style='color:red'>v
Veliki predavalnici Instituta »Jožef Stefan«</span></font> na
Jamovi cesti 39 v Ljubljani. Napovednik predavanja najdete tudi na naslovu <a
href="http://www.ijs.si/ijsw/Koledar_prireditev">http://www.ijs.si/ijsw/Koledar_prireditev</a>,
posnetke preteklih predavanj<font color=blue><span style='color:blue'> </span></font>pa
na <a href="http://videolectures.net/kolokviji_ijs">http://videolectures.net/kolokviji_ijs</a>.
<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~<br>
<br>
<o:p></o:p></span></font></p>
<p class=MsoNormal><b><font size=3 color="#333399" face="Times New Roman"><span
style='font-size:12.0pt;color:#333399;font-weight:bold'>Prof. James F. Scott<o:p></o:p></span></font></b></p>
<p class=MsoNormal style='text-align:justify;text-justify:inter-ideograph'><i><font
size=3 face="Times New Roman"><span style='font-size:12.0pt;font-style:italic'>Department
of Physics, Cavendish Laboratory, <st1:City w:st="on"><st1:place w:st="on">Cambridge</st1:place></st1:City>,
University, Velika Britanija<o:p></o:p></span></font></i></p>
<p class=MsoNormal style='text-align:justify;text-justify:inter-ideograph'><i><font
size=3 face="Times New Roman"><span style='font-size:12.0pt;font-style:italic'><o:p> </o:p></span></font></i></p>
<p class=MsoNormal style='text-autospace:none'><b><font size=3
face="Times New Roman"><span style='font-size:12.0pt;font-weight:bold'><o:p> </o:p></span></font></b></p>
<p class=MsoBodyText><b><font size=4 face="Times New Roman"><span
style='font-size:14.0pt;position:relative;top:0pt;mso-text-raise:0pt;
font-weight:bold'>Zakaj moramo študirati tudi izolatorje?<o:p></o:p></span></font></b></p>
<p class=MsoNormal style='text-autospace:none'><b><font size=3
face="Times New Roman"><span style='font-size:12.0pt;font-weight:bold'><o:p> </o:p></span></font></b></p>
<p class=MsoNormal style='text-align:justify;text-justify:inter-ideograph;
text-indent:35.4pt'><font size=2 face="Times New Roman"><span style='font-size:
11.0pt'>Superprevodniki so zelo atraktivni materiali, polprevodniki pa so
milijardni posel. Zakaj naj bi torej znanstveniki sploh študirali izolatorje?
Najprej, večina magnetnih materialov je izolatorskih. Drugič, tudi vsi
feroelektriki so izolatorji. Torej, materiali, kjer najdemo hkrati magnetne in
feroelektrične lastnosti so po definiciji izolatorji. V preteklih letih so
raziskave izolatorskih materialov ubrale nove poti: študij naprav nanometrskih
dimenzij, vključno s senzorji, aktuatorji ter pretvorniki. Prvo, kar lahko
opazimo, je, da ko napravimo izolator dovolj tanek, začne dobro prevajati.
Kateri je torej mehanizem prevajanja: Poole-Frenkelovo, Schottkyjevo ali
Fowler-Nordheimovo tuneliranje? Drugič, feroelektriki in feromagneti imajo
domene – čim manjši je vzorec, tem manjše so domene. V naši skupini smo
razvili teorijo, ki dobro opiše vedenje feromagnetnih in feroelektričnih
materialov dimenzij med 2 nm in <st1:metricconverter ProductID="2 mm" w:st="on">2
mm</st1:metricconverter> – torej obseg 6 redov velikosti – brez
kakršnih koli prostih parametrov. Odkrili smo, da so domene zaokrožene in
fraktalne. Na koncu se bomo posvetili materialom, ki so hkrati magnetni in
feroelektrični. Gilbert je leta 1600 pokazal, da sta elektrostatika in
magnetizem nepovezana. Vendar to ni čisto res! Pokazali bomo nekaj
feroelektričnih spominskih elementov, vključno s tistimi, ki so vgrajeni v SONY
Playstation.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=3 face=Calibri><span style='font-size:12.0pt;
font-family:Calibri'><o:p> </o:p></span></font></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;margin-bottom:12.0pt'><font
size=3 face="Times New Roman"><span style='font-size:12.0pt'>Predavanje bo v
angleščini.<o:p></o:p></span></font></p>
<pre><font size=3 face="Times New Roman"><span style='font-size:12.0pt;
font-family:"Times New Roman"'><o:p> </o:p></span></font></pre><pre><strong><b><font
size=3 color=red face=Calibri><span style='font-size:12.0pt;font-family:Calibri;
color:red'>Lepo vabljeni!<o:p></o:p></span></font></b></strong></pre><pre
style='text-align:center'><strong><b><font size=6 color=red face=Calibri><span
style='font-size:24.0pt;font-family:Calibri;color:red'><o:p> </o:p></span></font></b></strong></pre>
<p class=MsoNormal align=center style='text-align:center'><b><font size=6
face="Times New Roman"><span lang=EN-US style='font-size:24.0pt;font-weight:
bold'>***<o:p></o:p></span></font></b></p>
<p class=MsoNormal style='text-align:justify;text-justify:inter-ideograph'><font
size=3 face="Times New Roman"><span lang=EN-US style='font-size:12.0pt'><o:p> </o:p></span></font></p>
<p class=MsoNormal style='text-align:justify;text-justify:inter-ideograph'><font
size=3 face="Times New Roman"><span lang=EN-US style='font-size:12.0pt'>We would
like to invite you to 13<sup>th</sup> lecture of the "Kolokvij na
IJS" ("Days of Jožef Stefan") in the school year 2008/09. The
lecture will be held <b><span style='font-weight:bold'>on Thursday, Mar 26 2009,
at 1 pm</span></b> at <b><span style='font-weight:bold'>JSI main lecture hall</span></b>,
Jamova 39, <st1:place w:st="on"><st1:City w:st="on">Ljubljana</st1:City></st1:place>.
The abstract of the lecture can be found on website: </span></font><font
size=2><span lang=EN-US style='font-size:10.0pt'><a
href="http://www.ijs.si/ijsw/Koledar_prireditev"><font size=3><span
style='font-size:12.0pt'>http://www.ijs.si/ijsw/Koledar_prireditev</span></font></a></span></font><span
lang=EN-US>, the previous recorded lectures can be found on website: </span><font
size=2><span lang=EN-US style='font-size:10.0pt'><a
href="http://videolectures.net/kolokviji_ijs"><font size=3><span
style='font-size:12.0pt'>http://videolectures.net/kolokviji_ijs</span></font></a></span></font><span
lang=EN-US>.</span><font size=2><span lang=EN-US style='font-size:10.0pt'> </span></font><span
lang=EN-US><o:p></o:p></span></p>
<p class=MsoNormal style='text-autospace:none'><font size=3
face="Times New Roman"><span lang=EN-US style='font-size:12.0pt'>********************************************<br>
<br>
</span></font><b><span style='font-weight:bold'><o:p></o:p></span></b></p>
<p class=MsoNormal style='text-autospace:none'><font size=2 face="Courier New"><span
style='font-size:10.0pt;font-family:"Courier New"'><o:p> </o:p></span></font></p>
<p class=MsoNormal style='text-align:justify;text-justify:inter-ideograph'><b><font
size=3 color="#333399" face="Times New Roman"><span lang=EN-US
style='font-size:12.0pt;color:#333399;font-weight:bold'>Prof. James F. Scott <o:p></o:p></span></font></b></p>
<p class=MsoNormal style='text-align:justify;text-justify:inter-ideograph'><i><font
size=3 face="Times New Roman"><span lang=EN-US style='font-size:12.0pt;
font-style:italic'>Department of Physics, Cavendish Laboratory, <st1:place
w:st="on"><st1:City w:st="on">Cambridge University</st1:City>, <st1:country-region
w:st="on">UK</st1:country-region></st1:place><o:p></o:p></span></font></i></p>
<p class=MsoNormal style='text-autospace:none'><b><font size=3
face="Times New Roman"><span style='font-size:12.0pt;font-weight:bold'><o:p> </o:p></span></font></b></p>
<p class=MsoNormal style='text-align:justify;text-justify:inter-ideograph'><b><font
size=4 face="Times New Roman"><span lang=EN-US style='font-size:14.0pt;
font-weight:bold'>Why study insulators?<o:p></o:p></span></font></b></p>
<p class=MsoNormal style='text-autospace:none'><font size=3
face="Times New Roman"><span style='font-size:12.0pt'><o:p> </o:p></span></font></p>
<p class=MsoNormal style='text-align:justify;text-justify:inter-ideograph;
text-indent:36.0pt'><font size=3 face="Times New Roman"><span lang=EN-US
style='font-size:12.0pt'>Superconductors are sexier and semiconductors produce
a billion $ per year in devices. So why should scientists study insulating
materials? Firstly, most magnets are insulators; and second, all ferroelectrics
(which switch charge in an applied voltage) are insulators. So phenomena that
involve magnetism or ferroelectricity (piezoelectricity and pyroelectricity)
are generally insulating. In the past few years the study of insulating
materials has taken two new directions: The study of nano-devices, including
sensors, actuators, and transducers. The first thing one discovers is that if
you make an insulating material thin enough, it conducts quite well. And what
are the conduction mechanisms: Poole-Frenkel, Schottky, Fowler-Nordheim
tunneling, space-chage-limited? The second thing one finds is that
ferroelectrics and ferromagnets have domains -- and the smaller the object, the
smaller its domains. We have developed a theory of nano-domains that works in
all magnets and ferroelectrics from 2 nm in size to 2 mm -- six orders of
magnitude -- with no adjustable parameters. We also find domains that are round
instead of rectangular and fractal instead of integer in dimension. <o:p></o:p></span></font></p>
<p class=MsoNormal style='text-align:justify;text-justify:inter-ideograph;
text-indent:36.0pt'><font size=3 face="Times New Roman"><span lang=EN-US
style='font-size:12.0pt'>Finally, I will talk about materials that are
simultaneously magnetic and ferroelectric. Gilbert showed in 1600 that
electrostatics and magnetism are unrelated -- but that isn't quite true. If
time permits I will show some ferroelectric memories, including the ones in the
SONY Playstation.<o:p></o:p></span></font></p>
<p class=MsoNormal style='text-align:justify;text-justify:inter-ideograph;
text-indent:36.0pt'><font size=3 face="Times New Roman"><span lang=EN-US
style='font-size:12.0pt'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span lang=EN-US
style='font-size:12.0pt'><o:p> </o:p></span></font></p>
<p class=MsoNormal><b><font size=4 face="Times New Roman"><span lang=EN-US
style='font-size:14.0pt;font-weight:bold'>We look forward to meeting you at the
“Kolokvij na IJS”!<o:p></o:p></span></font></b></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-US style='font-size:
10.0pt;font-family:Arial'><o:p> </o:p></span></font></p>
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