Dr Debangsu Roy
Dr. Debangsu Roy
Assistant Professor
debangsu@iitrpr.ac.in
+91-1881-242159
https://sites.google.com/view/debangsu
219, TC

Biography

Debangsu Roy is an Assistant Professor at the Department of Physics at IIT Ropar. He received his MS and PhD from Indian Insitute of Science, Bangalore, India. During his PhD at the Department of Physics at the Indian Institute of Science, India, he investigated the oxide exchange spring behavior in bulk as well as thin films. The realization of the exchange spring behavior as well as the improvement of the magnetic energy product employing exchange spring concept in oxide system has been demonstrated successfully during his doctoral work. As a postdoctoral associate at Lior Klein’s Lab at Bar Ilan Univeristy, Israel, Dr. Roy worked on the devices made of itinerant  ferromagnet SrRuO3.  It is found that the Hall effect resistivity in ultra clean SrRuO3 cannot be described as a sum of the ordinary and the anomalous Hall effect;  both the mechanism are effectively intermixed which could be linked to the predicted existence of Weyl nodes in SrRuO3. In addition, the effect of applied magnetic fields on the interface resistance of the domain walls as well as the domain wall depinning in SrRuO3 has also been investigated. During his second postdoctoral stint in Prof. Andrew Kent’s group in New York University, Dr. Roy investigated the spin transport and spin transfer mechanism in AFM insulators using DC, high frequency transport and X-ray spectroscopy with a goal to probe the AFM order in these insulators.  


Area of Research

Spintronics


Education

  • 2008-2013: Ph.D., Indian Institute of Science, Bangalore, India.
  • 2005-2008: M.S., Physics, Indian Institute of Science, Bangalore, India.
  • 2002-2005: B.Sc., Physics (Major), Calcutta University.


Work Experience

  • August, 2018-Present : Assistant Professor, Department of Physics, IIT Ropar, India.
  • Oct, 2016-August, 2018 : Postdoctoral Associate, New York University, USA.
  • November, 2013-July,2016: Postdoctoral Research Scholar, Bar Ilan University, Israel.


Other Information

https://sites.google.com/view/debangsu 

Research

Spin physics in Insulators A central theme in spintronics is the inter-conversion of charge and spin currents. Recently, a focus has been on magnetic insulators where spin transport occurs through spin-wave propagation and spin currents can be generated by either spin injection or thermal gradients. These phenomena can be studied in simple bilayer films consisting of a ferrimagnetic (FIM) or Antiferromagnetic (AFM) insulator, and heavy metal (HM) with large spin-orbit coupling such as Pt,W and so on. Spin to charge current conversion in such bilayers occurs by the inverse spin-Hall and Rashba-Edelstein effects. Spin to charge conversion enables determination of the spin Seebeck effect (SSE). A thermal gradient across the FIM film produces a spin current into a neighboring heavy metal film, resulting in a transverse charge current or a voltage across the heavy metal film in an open circuit situation. Recent studies have demonstrated significant torques associated with thermally generated spin currents in magnetic tunnel junctions. Thermal gradients, thus, provide a convenient route to characterize the spin transport as well as a means to study the inverse effects, such as the spin torque on the AFM/ FIM magnetization in response to spin currents associated with charge current flow in the HM.

Spin-Orbit Torque in Magnetic Heterostructures In this project, the origin of spin-orbit torques in various multilayers is investigated. Generally, two distinct effects namely spin Hall effect and Rashba-Edelstein effects attribute to the spin-orbit torque. However, the relative importance of these two effects remains elusive. In this regard, devices made of different multilayer films are investigated. The underlying mechanism would lead to the design of a system with enhanced spin-to charge conversion efficiency and manipulate the spin-orbit torques, which in turn provide new functionality for manipulating spin states in magnetic materials.


Group Member

  • Raghvendra Posti (Ph.D. student)
  • Abhishek Kumar (Ph.D. student)

Lab Facility


Publications

Open Position

Teaching