Speaker
Markus Müller
(PSI - Paul Scherrer Institut)
Description
Multiferroism can originate from the breaking of inversion symmetry caused by magnetic-spiral order. It usually arises due to competing magnetic exchange interactions that differ by their range and sign, and thus occurs at low temperatures. I present a mechanism that works at much higher temperatures. It relies on frustrating bonds randomly introduced along a single crystallographic direction, as found in a realistic model of YBaCuFeO5, where spiral order at high temperatures was indeed reported. We predict a correlation between the ordering temperature and the spiral wavevector. We show that spin orbit coupling at impurities induces a tilting of the easy plane, which ensures that spiral order couples to electric polarization.
Primary authors
Markus Müller
(PSI - Paul Scherrer Institut)
Dr
Andrea Scaramucci
(ETHZ)
Dr
Christopher Mudry
(PSI)
Prof.
Maxim Mostovoy
(Groningen)
Dr
Hiroshi Shinaoka
(Tokyo)
Prof.
Matthias Troyer
(ETHZ)
Prof.
Nicola Spaldin
(ETHZ)
