SSL Seminar Series 2005 No.9

Date: 19 September (Monday), 2005
Time: 4:00pm-5:00pm
Venue: Physics Resource Room (Blk S13 # 02-16)

Speaker: Dr R. Mahendiran
Title: Nano-, Meso- & Macro scale phase in colossal magnetoresistance (CMR) oxides

Abstract:
Colossal Magnetoresistance (CMR) in transition metal oxides is one of the hot topics in physics and chemistry. Among all the transition metal oxides, the family of manganites which has the general formula R 1-x A x MnO3 ( R = La3+, Pr3+, Nd3+, etc.. A = Ca2+, Sr2+, Ba2+ etc.,) shows striking changes in electrical resistance in response to several stimuli such as magnetic field, light, X-ray, strain, temperature etc. These oxides are also testing ground for theories based on strong correlation effects. One of the perplexing properties of these oxides is the existence of magnetic (also structural ) domains of various sizes (nano, meso and micron sizes) embedded in a matrix whose magnetic and electric properties are different from the nano- or meso scale structures. It is still not clear why such multi scale structures appear. I will discuss the current status of our understanding about these multiscale structures and their impact on CMR and other properties.