Tuning of Magnetic Properties of nano-structured materials developed by novel synthetic strategies

Rabi Narayan Panda

Department of Chemistry, Birla Institute of Technology and Science

Pilani, K. K. Birla, Goa Campus, Goa, India

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Abstract

Recent advances on novel synthesis, characterizations and magnetic properties on selected Fe, Co and Ni based alloys and nitrides will be presented. The model materials systems studied include: Ni-Co, Fe-Co-N and Fe-Ni-N etc. It has been already observed that in nano-dimensional particulate structures, several factors such as: size, shape, surface structures, lattice stain, dipolar interactions, long range ordering etc., play very important role in establishing magnetic properties. These factors diversely affect the magnetic characteristics and are strictly dependent on material structures. These alteration of material-structures is in turn sensitive to synthesis procedure. Therefore, the present contribution would focus on correlating material structures with magnetic characteristics for the above mentioned materials systems which are developed using various novel and newer synthesis methodologies.

Oleic acid and oleyl amine coated Ni-Co materials were developed by using novel chemical reduction technique in single step. The materials were also embedded in silica matrix in order to study the properties arising from such nano-inclusion. Fe-Co-N and Fe-Ni-N nano-structures were fabricated using chemical precursors synthesized by novel route and its subsequent nitridation using NH3(g). The exhaustive characterizations including spectroscopic techniques, XRD, electron microscopy, BET surface areas have been carried out. In order to study magnetic properties, M Vs H and FC-ZFC at low temperature have been measured. The magnetic properties were correlated with size, shape, surface structure and dipolar interactions. Interesting magnetic properties such as: large enhancements of magnetizations were obtained for Co-Ni, Co-Fe-N and Ni-Fe-N nano-material systems. The results were correlated with altered materials structure having excess induced strain and reduced dimensionality.

References:

1.  Shankar B. Dalavi andRabi N. Panda, Journal of Materials Research, 31 (16) 2016,2430.

2.  Pragnya P. Mishra, M. Manivel Raja and Rabi N. Panda, Journal of Superconductivity and Novel Magnetism 29 (5), (2016) 1347.

3.  Pragnya P. Mishra, M. Manivel Raja and Rabi N. Panda, Mater. Res. Bull. 75, (2016) 127.