Preparation, characterization, electrical and magnetic properties of Mn-doped dilute magnetic semiconductors

Abstract

Nanoparticle dilute magnetic semiconductors (DMS) are becoming increasingly important due to their possible applications in spintronics, an emerging field where the conduction process in the materials is a spin-based process. Nanoparticles of Mn-doped ZnO (DMS) material with general formula Zn sub(1-x)Mn sub(x) O (x¼ 0:05; 0:15; 0:2) were prepared by opting single stage combustion synthesis process. The samples characterized, exhibited formation of monophasic nanoparticles of the sample with average particle size ranging between 17 nm to 23 nm. The calculations of energy bandgap made from UV absorption spectra showed variation of the bandgap from 2.18 eV to 2.32 eV. The magnetic measurements (VSM) made on the samples becomes sharper for sample with higher Mn concentration. con¯rmed formation of a single diamagnetic (Zn sub(0:95)Mn sub(0:05)O) and two namely (Zn sub(0:85)Mn sub(0:15)O) (Zn sub(0:8)Mn sub(0:2)O) paramagnetic samples. It is interesting to see that all the three magnetic profiles exhibit hysteresis type behavior both in diamagnetic form and paramagnetic form. The resistivity of the samples was of the order of 1010 Ohm-cm (-cm) at lower temperatures. Temperature- dependent resistivity curves exhibited peaking behavior for all the three samples which is very interesting. Temperature-dependent thermo-power profiles give an indication of n-type semiconductor behavior with significantly deep and broad minima around 100 degrees C which becomes sharper for sample with higher Mn concentration.