1. Department of Materials Science and Metallurgical Engineering, Indian Institute of Technology Hyderabad, Hyderabad502204, Telangana, India
2. Phase Change Memory Lab, Advanced Memory and Computing Group, Department of Electrical Engineering, Indian Institute of Technology Madras, Chennai600036, India
3. Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Forschungszentrum Jülich, Jülich52425, Germany