Berlin 2012 – scientific programme
Parts | Days | Selection | Search | Updates | Downloads | Help
TT: Fachverband Tiefe Temperaturen
TT 45: Correlated Electrons: Poster Session
TT 45.82: Poster
Thursday, March 29, 2012, 15:00–19:00, Poster B
Thermal expansion investigation on EuB6 — •Rudra Sekhar Manna1, Frank Schnelle1, Mariano de Souza1, Michael Lang1, Pintu Das1, Adham Amyan1, Jens Müller1, Stephan von Molnár2, Peng Xiong2, and Zachary Fisk3 — 1Physics Institute, Goethe-University Frankfurt (M), SFB/TR 49, D-60438 Frankfurt (M), Germany — 2Department of Physics, Florida State University, Tallahassee, Florida 32306, USA — 3Dept. of Physics, University of California, Irvine, California 92697, USA
EuB6 is a semimetallic correlated electron system, which exhibits a complex sequence of electronic and magnetic phase transitions at ∼ 15.5 K (T1) and 12.5 K (T2). The material also shows a colossal magnetoresistance effect which is largest at T1. The paramagnetic to ferromagnetic transition in this system is suggested to take place via the formation of magnetic polarons. In this work, we investigate by means of thermal expansion and magnetostriction measurements to which extent lattice degrees of freedom are involved in these phase transitions. We find two corresponding anomalies in the thermal expansion, the one occurring at T2 being much larger than that at T1. The anomalies are very sensitive to magnetic fields. By applying a small magnetic field of less than 50 mT the anomaly at T1 is fully suppressed, while the lower-temperature anomaly at T2 shifts to higher temperature as the field is increased and finally fades out at a field B > 5 T. These measurements are complemented by measurements of the magnetostriction at various temperatures from below T2 to above T1 which highlight the extraordinarily large magnetoelastic effects in this material.