Magnetic Behaviour of Co Doped CdSe Nanoparticles as Dilute Magnetic Semiconductor

Abstract

Over the past ten years, the search for compounds combining the properties of semiconductors and ferromagnets has evolved into an important field of materials science. A large portion of the present research is devoted to the II-VI and III-V based dilute magnetic semiconductor. One of today’s challenges for the development of future technologies is the realization of devices that control not only the electron charge, as in present electronics, but also its spin, setting the basis for future spintronics. Spintronics represents the concept of the synergetic and multifunctional use of charge and spin dynamics of electrons, aiming to go beyond the semiconductor electronics and magnetic storage technology. The most direct method to induce spin-polarized electrons into a semiconductor is by introducing appropriate transition-metal or rare-earth dopants producing a dilute magnetic semiconductor (DMS). The DMS are semiconducting materials in which a fraction of the host cations can be substitutionally replaced by magnetic ions. These DMS are the building blocks of the future “Spintronics” devices. Undoped and Co-doped CdSe dilute magnetic semiconductors have been synthesized by solvothermal technique in which SDS (sodium doceyl sulphate) is used as capping agent for stability. The structural and phase analysis is done with the help of X-ray diffraction (XRD). UV-Visible absorption spectroscopy is used for the study of the optical properties. The morphology of the synthesized nanoparticles is analyzed by transmission electron microscope. Superconducting quantum interference device (SQUID) is used for the magnetic study and Energy dispersive X-ray spectroscopy (EDX) is used for the elemental analysis. The pure CdSe nanoparticles show diamagnetic behavior and they are non uniform but Co doped CdSe nanoparticle shows ferromagnetic behaviour with spherical shape.