<html><body><div style="font-family: arial, helvetica, sans-serif; font-size: 12pt; color: #000000"><div data-marker="__QUOTED_TEXT__"><div style="font-family: 'arial' , 'helvetica' , sans-serif; font-size: 12pt; color: #000000;" data-mce-style="font-family: 'arial' , 'helvetica' , sans-serif; font-size: 12pt; color: #000000;"><div><div id="zimbraEditorContainer" style="font-family: 'arial' , 'helvetica' , sans-serif; font-size: 12pt; color: #000000;" class="1" data-mce-style="font-family: 'arial' , 'helvetica' , sans-serif; font-size: 12pt; color: #000000;"><div><div style="font-family: 'arial' , 'helvetica' , sans-serif; font-size: 12pt; color: #000000;" data-mce-style="font-family: 'arial' , 'helvetica' , sans-serif; font-size: 12pt; color: #000000;"><div><div><div><div align="center"><img src="cid:83a42f6243d6ce6f98242ca802c425259a3eaf05@zimbra" data-mce-src="cid:83a42f6243d6ce6f98242ca802c425259a3eaf05@zimbra"><br>Seminar@IF, Thursday September 30th 2021 at 11:00, room ``Mladen Paić", 3rd wing, and Zoom<br><br><strong><span style="color: #55913c; font-family: 'roman';" data-mce-style="color: #55913c; font-family: 'roman';"><span style="font-size: 21.3333px;" data-mce-style="font-size: 21.3333px;"><span style="font-family: 'times new roman' , serif;" data-mce-style="font-family: 'times new roman' , serif;"><span class="markedContent" id="page3R_mcid10"><span style="font-size: 16pt; font-family: 'times new roman' , 'new york' , 'times' , serif;" data-mce-style="font-size: 16pt; font-family: 'times new roman' , 'new york' , 'times' , serif;"><span dir="ltr">Photo</span><span dir="ltr">-</span><span dir="ltr">induced structural dynamics in Magnetit</span><span dir="ltr">e</span></span></span></span></span></span></strong><b><br></b><div><span style="font-family: 'century gothic' , sans-serif; font-size: 14pt;" data-mce-style="font-family: 'century gothic' , sans-serif; font-size: 14pt;"><b><span class="markedContent" id="page3R_mcid1"><span style="font-family: sans-serif;" dir="ltr" data-mce-style="font-family: sans-serif;">D</span><span style="font-family: sans-serif;" dir="ltr" data-mce-style="font-family: sans-serif;">r</span><span style="font-family: sans-serif;" dir="ltr" data-mce-style="font-family: sans-serif;">.Siham Benhabib</span></span></b></span></div><div style="color: #000000;" data-mce-style="color: #000000;"> </div><div style="text-align: center;" data-mce-style="text-align: center;"><div><span style="font-family: 'century gothic' , sans-serif;" data-mce-style="font-family: 'century gothic' , sans-serif;"><span style="font-size: 14.6667px;" data-mce-style="font-size: 14.6667px;"><b><span class="markedContent" id="page3R_mcid5" style="font-size: 11pt;" data-mce-style="font-size: 11pt;"><span style="font-family: sans-serif;" dir="ltr" data-mce-style="font-family: sans-serif;">EPFL</span><span style="font-family: sans-serif;" dir="ltr" data-mce-style="font-family: sans-serif;">, Lausanne, </span><span style="font-family: sans-serif;" dir="ltr" data-mce-style="font-family: sans-serif;">Switzerland</span></span></b></span></span></div></div></div><br><div style="text-align: justify;" data-mce-style="text-align: justify;" align="justify"><span style="font-size: 10pt;" data-mce-style="font-size: 10pt;"><span class="markedContent" id="page3R_mcid12"><span style="font-family: sans-serif;" dir="ltr" data-mce-style="font-family: sans-serif;"> <span style="font-size: 11pt;" data-mce-style="font-size: 11pt;">The complex interplay between crystal structure, charge, and orbital orders leads </span></span><span style="font-size: 11pt;" data-mce-style="font-size: 11pt;"><span style="font-family: sans-serif;" dir="ltr" data-mce-style="font-family: sans-serif;">magnetite to undergo atypical metal</span><span style="font-family: sans-serif;" dir="ltr" data-mce-style="font-family: sans-serif;">-</span><span style="font-family: sans-serif;" dir="ltr" data-mce-style="font-family: sans-serif;">insulator transition in the neighborhood </span><span style="font-family: sans-serif;" dir="ltr" data-mce-style="font-family: sans-serif;">of 125 K </span><span style="font-family: sans-serif;" dir="ltr" data-mce-style="font-family: sans-serif;">known by Verwey Transition (VT). Despite the numerous approaches that have been </span><span style="font-family: sans-serif;" dir="ltr" data-mce-style="font-family: sans-serif;">adopted in the last 80 years, the leading mechanism of VT in magnetite still remains </span><span style="font-family: sans-serif;" dir="ltr" data-mce-style="font-family: sans-serif;">ambiguous. Here we use ultrafast electron diffraction (UED) to trace the structura</span><span style="font-family: sans-serif;" dir="ltr" data-mce-style="font-family: sans-serif;">l </span><span style="font-family: sans-serif;" dir="ltr" data-mce-style="font-family: sans-serif;">changes of magnetite across the VT in the thermodynamic equilibrium and the ultrafast </span><span style="font-family: sans-serif;" dir="ltr" data-mce-style="font-family: sans-serif;">dynamics </span><span style="font-family: sans-serif;" dir="ltr" data-mce-style="font-family: sans-serif;">response </span><span style="font-family: sans-serif;" dir="ltr" data-mce-style="font-family: sans-serif;">of </span><span style="font-family: sans-serif;" dir="ltr" data-mce-style="font-family: sans-serif;">the </span><span style="font-family: sans-serif;" dir="ltr" data-mce-style="font-family: sans-serif;">structure </span><span style="font-family: sans-serif;" dir="ltr" data-mce-style="font-family: sans-serif;">under </span><span style="font-family: sans-serif;" dir="ltr" data-mce-style="font-family: sans-serif;">femtosecond </span><span style="font-family: sans-serif;" dir="ltr" data-mce-style="font-family: sans-serif;">pulsed </span><span style="font-family: sans-serif;" dir="ltr" data-mce-style="font-family: sans-serif;">excitations. </span></span><span style="font-size: 11pt;" data-mce-style="font-size: 11pt;"><span style="font-family: sans-serif;" dir="ltr" data-mce-style="font-family: sans-serif;">Specifically, we study the strain evolution in magnetite following two major steps. </span><span style="font-family: sans-serif;" dir="ltr" data-mce-style="font-family: sans-serif;"> </span></span></span><span class="markedContent" id="page3R_mcid13" style="font-size: 11pt;" data-mce-style="font-size: 11pt;"><span style="font-family: sans-serif;" dir="ltr" data-mce-style="font-family: sans-serif;">First, in </span><span style="font-family: sans-serif;" dir="ltr" data-mce-style="font-family: sans-serif;">the thermodynamic equilibrium, we used symmetry arguments to determine </span><span style="font-family: sans-serif;" dir="ltr" data-mce-style="font-family: sans-serif;">the symmetry of the order parameter responsible for strain changes across VT. </span><span style="font-family: sans-serif;" dir="ltr" data-mce-style="font-family: sans-serif;"> </span></span></span><span class="markedContent" id="page3R_mcid14"><span style="font-size: 11pt;" data-mce-style="font-size: 11pt;"><span style="font-family: sans-serif;" dir="ltr" data-mce-style="font-family: sans-serif;">Second, </span><span style="font-family: sans-serif;" dir="ltr" data-mce-style="font-family: sans-serif;">out</span><span style="font-family: sans-serif;" dir="ltr" data-mce-style="font-family: sans-serif;">-</span><span style="font-family: sans-serif;" dir="ltr" data-mce-style="font-family: sans-serif;">of</span><span style="font-family: sans-serif;" dir="ltr" data-mce-style="font-family: sans-serif;">-</span><span style="font-family: sans-serif;" dir="ltr" data-mce-style="font-family: sans-serif;">equilibrium </span><span style="font-family: sans-serif;" dir="ltr" data-mce-style="font-family: sans-serif;">evolution: </span><span style="font-family: sans-serif;" dir="ltr" data-mce-style="font-family: sans-serif;">we </span><span style="font-family: sans-serif;" dir="ltr" data-mce-style="font-family: sans-serif;">investigated </span><span style="font-family: sans-serif;" dir="ltr" data-mce-style="font-family: sans-serif;">strain </span><span style="font-family: sans-serif;" dir="ltr" data-mce-style="font-family: sans-serif;">behavior </span><span style="font-family: sans-serif;" dir="ltr" data-mce-style="font-family: sans-serif;">under </span><span style="font-family: sans-serif;" dir="ltr" data-mce-style="font-family: sans-serif;">femtosecond pulsed light excit</span><span style="font-family: sans-serif;" dir="ltr" data-mce-style="font-family: sans-serif;">ations. We used two excitations, 800 nm and 400nm </span><span style="font-family: sans-serif;" dir="ltr" data-mce-style="font-family: sans-serif;">(1.6 and 3.09 eV, respectively). These investigations are carried out in two phases, </span><span style="font-family: sans-serif;" dir="ltr" data-mce-style="font-family: sans-serif;">above and below VT termed as High Temperature (HT) and Low Temperature (LT) </span><span style="font-family: sans-serif;" dir="ltr" data-mce-style="font-family: sans-serif;">phases. In the LT phase, we distinguish two d</span><span style="font-family: sans-serif;" dir="ltr" data-mce-style="font-family: sans-serif;">ifferent time evolution of the strain </span><span style="font-family: sans-serif;" dir="ltr" data-mce-style="font-family: sans-serif;">depending on the excitation’s energy. This difference is absent in the HT phase. We </span><span style="font-family: sans-serif;" dir="ltr" data-mce-style="font-family: sans-serif;">presume </span><span style="font-family: sans-serif;" dir="ltr" data-mce-style="font-family: sans-serif;">this </span><span style="font-family: sans-serif;" dir="ltr" data-mce-style="font-family: sans-serif;">difference </span><span style="font-family: sans-serif;" dir="ltr" data-mce-style="font-family: sans-serif;">is </span><span style="font-family: sans-serif;" dir="ltr" data-mce-style="font-family: sans-serif;">intimately </span><span style="font-family: sans-serif;" dir="ltr" data-mce-style="font-family: sans-serif;">linked </span><span style="font-family: sans-serif;" dir="ltr" data-mce-style="font-family: sans-serif;">to </span><span style="font-family: sans-serif;" dir="ltr" data-mce-style="font-family: sans-serif;">the </span><span style="font-family: sans-serif;" dir="ltr" data-mce-style="font-family: sans-serif;">mechanism </span><span style="font-family: sans-serif;" dir="ltr" data-mce-style="font-family: sans-serif;">of </span><span style="font-family: sans-serif;" dir="ltr" data-mce-style="font-family: sans-serif;">VT. </span><span style="font-family: sans-serif;" dir="ltr" data-mce-style="font-family: sans-serif;">In </span><span style="font-family: sans-serif;" dir="ltr" data-mce-style="font-family: sans-serif;">this </span><span style="font-family: sans-serif;" dir="ltr" data-mce-style="font-family: sans-serif;">presentation, I will discuss the possible scenarios respo</span><span style="font-family: sans-serif;" dir="ltr" data-mce-style="font-family: sans-serif;">nsible for such differences in </span><span style="font-family: sans-serif;" dir="ltr" data-mce-style="font-family: sans-serif;">the dynamic responses</span></span><span style="font-size: 20px; font-family: sans-serif;" dir="ltr" data-mce-style="font-size: 20px; font-family: sans-serif;"> </span></span></div><br><b><span style="font-size: 12pt; font-family: 'century gothic' , sans-serif;" data-mce-style="font-size: 12pt; font-family: 'century gothic' , sans-serif;" lang="EN-GB"><span style="font-size: 11pt; font-family: 'century gothic' , sans-serif;" data-mce-style="font-size: 11pt; font-family: 'century gothic' , sans-serif;" lang="EN-GB"><span id="DWT704" class="ZmSearchResult"><span id="DWT713" class="ZmSearchResult">Seminar</span></span> hosts: <span class="Object" id="OBJ_PREFIX_DWT1009_ZmEmailObjectHandler"><span class="Object" id="OBJ_PREFIX_DWT53_ZmEmailObjectHandler"><span class="Object" id="OBJ_PREFIX_DWT114_ZmEmailObjectHandler"><span class="Object" id="OBJ_PREFIX_DWT705_ZmEmailObjectHandler"><span class="Object" id="OBJ_PREFIX_DWT714_ZmEmailObjectHandler"><a href="mailto:balog@ifs.hr" rel="nofollow%20noopener%20noreferrer%20nofollow%20noopener%20noreferrer nofollow noopener noreferrer nofollow noopener noreferrer nofollow noopener noreferrer nofollow noopener noreferrer nofollow noopener noreferrer" target="_blank" data-mce-href="mailto:balog@ifs.hr">Ivan Balog</a></span></span></span></span></span> i <span class="Object" id="OBJ_PREFIX_DWT1010_ZmEmailObjectHandler"><span class="Object" id="OBJ_PREFIX_DWT54_ZmEmailObjectHandler"><span class="Object" id="OBJ_PREFIX_DWT115_ZmEmailObjectHandler"><span class="Object" id="OBJ_PREFIX_DWT706_ZmEmailObjectHandler"><span class="Object" id="OBJ_PREFIX_DWT715_ZmEmailObjectHandler"><a href="mailto:ddominko@ifs.hr" rel="nofollow%20noopener%20noreferrer%20nofollow%20noopener%20noreferrer nofollow noopener noreferrer nofollow noopener noreferrer nofollow noopener noreferrer nofollow noopener noreferrer nofollow noopener noreferrer" target="_blank" data-mce-href="mailto:ddominko@ifs.hr">Damir Dominko</a></span></span></span></span></span></span></span></b><br>________________________________________________________________________________<br></div><br><div><span style="color: #000000;" data-mce-style="color: #000000;">Potičemo slušatelje da, zbog epidemiološke situacije, u što većem broju prate seminar ``on-line" putem Zooma.</span></div><div><br></div><div><span style="color: rgb(255, 0, 0);" data-mce-style="color: #ff0000;">https://zoom.us/j/5081440931</span><br><br><span style="color: rgb(255, 0, 0);" data-mce-style="color: #ff0000;">Meeting ID: 508 144 0931</span><br><br></div><br><div>---<br></div><br><div>Due to the epidemiological situation, we encourage the audience to follow the seminar on-line via Zoom.<br></div><br><div><div><br></div><div><span style="color: rgb(255, 0, 0);" data-mce-style="color: #ff0000;">https://zoom.us/j/5081440931</span><br><br><span style="color: rgb(255, 0, 0);" data-mce-style="color: #ff0000;">Meeting ID: 508 144 0931</span></div></div><div><br><pre class="moz-signature">--
Ivan Balog
Research associate
Institute of Physics Zagreb
Bijenicka cesta <span class="Object" id="OBJ_PREFIX_DWT708_com_zimbra_phone">46,
10000</span> Zagreb, Croatia
office: <span class="Object" id="OBJ_PREFIX_DWT709_com_zimbra_phone">+385 1 469 8908</span>
e-mail: <span class="Object" id="OBJ_PREFIX_DWT711_ZmEmailObjectHandler"><span class="Object" id="OBJ_PREFIX_DWT717_ZmEmailObjectHandler"><a href="mailto:ddominko@ifs.hr" rel="nofollow noopener noreferrer nofollow noopener noreferrer nofollow noopener noreferrer nofollow noopener noreferrer" target="_blank" data-mce-href="mailto:ddominko@ifs.hr">balog@ifs.hr</a></span></span></pre></div></div></div></div></div></div></div></div><br></div></div></body></html>