Research
Scanning Electron Microscopy (SEM) image of cobalt carbide nanoparticles
Image Courtesy: Dr. Nirmal Roy
Research Highlights
My research focuses on understanding the magnetism at nanoscale, especially in magnetic nanoparticles and low dimensional materials. Currently, we are working on an interesting system of cobalt carbide (Co2C ) nanoparticles that has a very high superparamagnetic blocking temperature. It also exhibits the exchange bias phenomenon concomitant with Kondo localization and has a low-temperature glassy phase. Recent Investigations have also been carried out to probe the magnetism microscopically with the help of the muon spin relaxation (µSR ) technique.
Micromagnetic Simulation of Exchange Bias in Co2C
FIG. (a) Schematic of the Co2C NPs having radii of \sim 40 nm with ferromagnetic (FM) core and spin-glass-like shell. (b) Bilayer structure of the sample used in simulation with a thin layer of spin-glass (SG) spins lying on top of an FM spin block. The solid lines refer to two cross-sections of the sample. Also shown are the different anisotropies and the applied field direction (c) Color-schemed polar (\theta ) and azimuthal (\phi ) angular variations of the SG spins defining their random orientations and shown as cross-sectional views with the cuts made along the two solid lines. The FM spins are shown in a saturated state. (d) – (f) Simulated hysteresis loops at different values of A_{int} and they are divided into three regimes from I to III.