Abstract—The capability of exploiting the electronic charge and spin properties simultaneously in a single material has made diluted magnetic semiconductors (DMS) remarkable in the field of spintronics. We report the designing of DMS based on zinc-blend ZnO doped with Cr impurity. The full potential linearized augmented plane wave plus local orbital FP-L(APW+lo) method in density functional theory (DFT) has been adapted to carry out these investigations. For treatment of exchange and correlation energy, generalized gradient approximations have been used. Introducing Cr atoms in the matrix of ZnO has induced strong magnetic moment with ferromagnetic ordering at stable ground state. Cr:ZnO was found to favor the short range magnetic interaction that reflect tendency of Cr clustering. The electronic structure of ZnO is strongly influenced in the presence of Cr impurity atoms where impurity bands appear in the band gap. Keywords—ZnO, Density functional theory, Diluted magnetic semiconductors, Ferromagnetic materials, FP-L(APW+lo). I. INTRODUCTION PINTRONICS or spin electronics is fast emerging field in the current information and technology. The significance of spintronics is the simultaneous manipulation of charge of electron for logic operations and its spin degree of freedom for data storage. The giant magneto resistance (GMR) is a well- known example of spintronics devices. It has several other applications such as spin valves [1], magnetic tunnel junctions [2], spin torque effects [3], domain wall devices [4] etc. However, the complete potential of a spintronic device has not been utilized yet because of inefficient spin injection in account of difference in resistivity of the magnetic/ semiconducting interface [5], [6]. DMS are alternating potential materials where magnetic impurity atoms are doped into semiconducting host to stimulate magnetization effect [7], [8]. Thus a single material exhibiting both semiconducting and magnetic features is considered as potential material for future spintronic applications [9]. A DMS with ferromagnetic properties at room temperature along with high magnetic moment, homogenously distributed dopants is considered as ideal for spintronic applications. Establishing such properties strongly depends on the selection of proper semiconductor host and magnetic impurity dopant material. Bakhtiar Ul Haq, R. Ahmed, A. Shaari, Mazmira binti Mohamed, and Nisar Ali are with the Department of Physics, Faculty of Science, Universiti Teknologi Malaysia, UTM Skudai, 81310 Johor, Malaysia (corresponding author e-mail: rashidahmed@utm.my). Among various semiconductors, GaN and ZnO doped with TM are claimed competent base material for fabrications of DMS [10]. The abundantly available and environmental friendly ZnO with its wide and direct band gap of 3.44 eV stand remarkable in this regard. Moreover, the TM has high solubility rate in the matrix of ZnO due to the nearly similar ionic radii of Zn(74pm) and other TM ions [11]. Among several other TM, Cr with ionic radii 73pm and high local magnetic moment of magnitude 4 μ B is remarkable dopant [12]-[15]. There have been several studies carried out on Cr:ZnO to investigate the ferromagnetic properties. However, there exist controversies in most of the studies reporting the ferromagnetism. References [16] and [13], [17], [18] have reported FM in Cr:ZnO at room temperature. The absence of FM has been reported in Cr:ZnO by [19]. In recent studies [20] has reported FM in Cr doped p-type ZnO. At room temperature and pressure, ZnO crystallizes in wurtzite (W) structure that is n-type in nature. Recent studies have reported the existence of ZnO in ZB phase [21], [22]. ZnO in meta stable ZB phase is reported to have lower carrier concentration compared to W phase and is expected to solve the long standing problem to control p-type conductivity. However, DMS based on ZB-ZnO is very scarcely explored particularly Cr doped ZB-ZnO. In the present work, we are investigating Cr doped ZnO base DMS in ZB phase. To execute this study, DFT based full potential linearized augmented plane wave plus local orbital method has been adapted in the WIEN2k package. For the treatment of exchange and correlation energy, the Perdew et al. [24] proposed generalized gradient approximation have been used. To realize magnetic effect in ZnO, 12.5% of Cr atoms are substituted on Zn sites. Our investigations for physical properties of Cr:ZnO cover the calculation of the lattice constants, spin polarized electronic band structures, density of states, and magnetic moment. II. COMPUTATIONAL DETAILS In the present study, we performed calculations for structural, electronic and magnetic properties of Cr:ZB-ZnO using DFT with FP-L(APW+lo) method. In this approach, simulated unit cell is divided into two (Muffin-Tin (MT) and interstitial) regions. In the former region, “a linear combination of the atomic like wave functions times the spherical harmonics” are used to expand “Kohn–Sham wave functions, charge density and potential” whereas in the later region, plane waves basis set is applied. Calculations have been done in WIEN2k code [23] which is the practical Cr Induced Magnetization in Zinc-Blende ZnO Based Diluted Magnetic Semiconductors Bakhtiar Ul Haq, R. Ahmed, A. Shaari, Mazmira Binti Mohamed, Nisar Ali S World Academy of Science, Engineering and Technology International Journal of Materials and Metallurgical Engineering Vol:9, No:2, 2015 164 International Scholarly and Scientific Research & Innovation 9(2) 2015 ISNI:0000000091950263 Open Science Index, Materials and Metallurgical Engineering Vol:9, No:2, 2015 publications.waset.org/10001240/pdf