STRUCTURAL, OPTICAL AND MAGNETIC STUDIES OF SnO2 BASED DILUTE MAGNETIC SEMICONDUCTORS

Abstract

During the past few years, the dilute magnetic semiconductors (DMS), in which a small fraction of atoms/ions is magnetic, have attracted considerable attention from both the fundamental as well as the application point of view. This is primarily due to the possibility that, in these DMS, the two degrees of freedom (i.e., spin and charge) can be independently tuned to realize multifunctional devices. In such devices, inducing stable room temperature ferromagnetism (RTFM) is one of the necessary prerequisites to realize any practical application of these materials. If thermally stable ferromagnetism can be induced while maintaining sufficiently high optical transparency in these oxides, new vistas of applications are possible with these semiconductors. In the present work, Sn02 is chosen .as the host semiconductor and manganese is used to induce DMS behavior in this host semiconductor matrix. In the present dissertation work entitled "Structural, Optical and Magnetic studies of Sn02 based dilute magnetic semiconductors'; thin films of doped and undoped Sn02 are prepared by Ultrasoinc Spray Pyrolysis Technique on glass and quartz substrates. Structural studies are performed by using XRD, FESEM, AFM, and EDAX. Optical studies are done by UV-visible-Spectrophotometer and Magnetic properties are studied using SQUID at low temperature (5K) & at room temperature (300K). The main objective of the present dissertation work is to study the effect of molarity concentration, substrate temperatures and doping concentration on the structural, optical, and magnetic properties of spray deposited pure and Mn doped Sn02 thin films. In the present study a correlation between structural, optical & magnetic properties of Mn doped Sn02 thin films is established and their dependency on substrate temperature and doping concentration is investigated. The possible mechanisms to explain the origin of observed room temperature ferromagnetism (RTFM) have been discussed.