DISORDER INDUCED MAGNETIC PHASE TRANSITIONS IN ITINERANT MAGNETS
ABSTRACT :
Although metallic ferromagnets have been studied extensively during the past several decades, new and interesting phenomena continue to appear even today. Novel magnetic phases in metals and alloys continue to offer new challenges to theory and experiments. In recent years, the focus has shifted from classical to quantum phase transitions (QPT) that occur at zero temperature under the influence of non-thermal parameters. Contemporary theories predict a new quantum critical point in disordered itinerant system with exotic phases and properties around this. The QPT has been reported in several rare-earth and few transition metal-based alloys. Interestingly, the observation of quantum Griffiths phase in Ni-V alloy system triggered the research activity in Ni-rich alloys to validate the proposed theoretical models. In the present talk, I will discuss the evolution of various magnetic phases that evolve through disorder and present some of our recent experimental results on Ni-based alloys. From the analysis of the low temperature physical properties on compositions close to quantum critical point, we attempt to identify the nature of phase transition in these alloys. These results along with variation of non-universal exponent obtained from magnetic isotherms corroborate well with the theoretical predictions.
ABOUT THE SPEAKER:
Srinivas Veeturi obtained his Ph.D degree in Physics from IIT Bombay (1987), then spent three years as a post-doc at Dalhousie University, Canada (1987-90). He was a visiting fellow at the Tata Institute of Fundamental Research, Bombay (1990-92). Subsequently, joined the department of Physics at IIT Kharagpur (1992- 2010). He also worked as a JSPS fellow at Nagoya University, Japan (2003), visiting scientist Royal Institute of Technology, Stockholm, Sweden (1999-2000) and Chungbuk National University, South Korea (2002). His current research interests include the study of magnetic and electrical properties of novel materials.