The innovation engine for new materials

What we can learn about multiferroics from high magnetic fields

Seminar Group: 


Vivien Zapf


Los Alamos National Laboratory


Friday, October 26, 2012 - 4:00pm


MRL Room 2053


Prof. Ram Seshadri

I will speak about the utility of high magnetic fields and the user program at the pulsed-field facility of the National High Magnetic Field Lab in Los Alamos and specifically how it applies to multiferroics. Multiferroics combine magnetic and electric order in insulating solid-state materials. They are necessary for many critical applications in sensing, energy storage and manipulation, data storage and manipulation, and high-frequency and high power devices. Several promising candidates for applications are being extensively explored by the multiferroics community including BiFeO3 and heterostructured materials. However no candidate material satisfies the complete wish-list of properties, which is strong coupling between large magnetic and electric net moments above room temperature. In particular, the strong coupling remains a sticking point. Recently at Los Alamos we have created a joint experiment-theory effort to go back to the drawing board and design and explore new coupling mechanisms between magnetism and ferroelectricity even if this means temporarily retreating to lower temperatures where we can better get a handle on underlying mechanisms. I will present coupling mechanisms based on 'up up down down' spins, trimers of spins, and trimers of trimers of spins. I will speak in particular Ca3CoMnO6 in which net magnetism couples to net ferroelectricity and illustrate how high magnetic fields are a tool for measuring the coupling and extracting other basic parameters necessary for modelling the magnetism.