Studies on multifunctional behaviour of Cr doped SrWO 4 Compounds M. Muralidharan 1 • V. Anbarasu 2 • A. Elaya Perumal 3 • K. Sivakumar 1 Received: 27 March 2015 / Accepted: 2 June 2015 / Published online: 9 June 2015 Ó Springer Science+Business Media New York 2015 Abstract Transition metal doped divalent tungstate compounds endowed with coalescence of optical and magnetic property forms a class of multifunctional mate- rials and found importance in the field of magneto-optical and spintronics device applications. In the present work, pure and Cr doped SrWO 4 compounds were synthesized by chemical precipitation method. Powder X-ray diffraction analysis reveals scheelite type tetragonal structure of all the compounds. The effect of doping on crystal symmetry and local structure of the compounds was investigated by Laser Raman spectroscopy studies. The micro sphere and poly- dispersed surface morphology of all the compounds were examined by scanning electron microscopy and transmis- sion electron microscopy analysis. Further, the evidences for oxygen vacancy and oxidation states of elements pre- sent in the compounds were analyzed by X-ray photo- electron spectroscopy. The optical absorption spectra explicitly describe the distinctive shift in absorption edge and linear decrease in band gap values while increasing Cr concentrations in SrWO 4 system. The presence of defective states and oxygen vacancy in Cr doped SrWO 4 compounds were confirmed with multicolor PL emission spectra. Electron paramagnetic resonance spectra authenticates the inducement of paramagnetic center (Cr 3? ) on increasing the dopant concentration. The magnetization analysis demonstrates enhanced ferromagnetic behaviour of all the Cr doped compounds, whereas the pure SrWO 4 compound exhibits frustrated ferromagnetic behaviour. The aug- mented ferromagnetic ordering in Cr doped compounds has been explained in terms of carrier-induced Ruderman– Kittel–Kasuya–Yosida interaction theory. The possible inducement of carrier mediated room temperature ferro- magnetism in Cr doped SrWO 4 explicit demonstrates a hopeful candidature for magneto- optical and spintronic device applications. 1 Introduction The quest for new dilute magnetic semiconducting (DMS) oxides have received greater attention in recent years due to their potential application in the field of memory devices and spin based electronic devices [1]. The basic idea of developing DMS materials is to use its multifunctional properties in spin based electronic devices, in which both charge carriers and spins are manipulated in a single compound without perturbing the semiconducting nature of the host material [2, 3]. Major challenges in spin based electronic devices are the optimization of life time stability of electron spin, the recent studies reveal the possibilities of solid state and optical spin injection in semiconducting oxide materials [4, 5]. In accordance to that, various tran- sition metal doped semiconducting oxides such as ZnO, MgO, HfO 2 , TiO 2 , SnO 2 , In 2 O 3 and ABO 3 structured materials (SrTiO 3 , BaTiO 3 and KTaO 3 ) have been widely investigated to achieve the stable spin based electronic devices [6–14]. However, the origin of ferromagnetism in non-magnetic oxides is still controvertial as the occurrence of ferromagnetic ordering is either by the effect of substi- tution/doping or the secondary phase formation of & M. Muralidharan rmmuralidharan@gmail.com 1 Department of Physics, Anna University, Chennai 600025, India 2 Department of Physics, Ramapuram Campus, SRM University, Chennai 600089, India 3 Department of Mechanical Engineering, Anna University, Chennai 600025, India 123 J Mater Sci: Mater Electron (2015) 26:6926–6938 DOI 10.1007/s10854-015-3311-x