Vol.:(0123456789) 1 3 Applied Physics A (2020) 126:559 https://doi.org/10.1007/s00339-020-03748-3 Dielectric and magnetic properties of dilute magnetic semiconductors Ag‑doped ZnO thin flms Zohra Nazir Kayani 1  · Ayesha Usman 2  · Hina Nazli 1  · Rifat Sagheer 1  · Saira Riaz 2  · Shahzad Naseem 2 Received: 9 March 2020 / Accepted: 22 June 2020 © Springer-Verlag GmbH Germany, part of Springer Nature 2020 Abstract Ag-doped ZnO thin flms are prepared by the cost-efective sol–gel dip-coating method at room temperature. The Ag dopant percentage varies between (2–10) wt%. The magnetic and dielectric properties have been studied. The dielectric and mag- netic properties of ZnO are signifcantly tailored by the increase in the Ag doping percentage. High dielectric constant and tangent loss have been observed at low frequencies which decreases with the increase in frequency. The AC conductivity is lower in the low-frequency region but has larger values in the high-frequency region. The ferromagnetic behavior of flms has been recorded at room temperature. Magnetic polarons play a pivotal role in the development of room temperature fer- romagnetism in Ag-doped ZnO thin flms. So, ferromagnetism in thin flms is governed by bound magnetic polarons. As the doping concentration increased, the saturation magnetization decreased and coercivity increased due to the combined efect of the decrease in crystallite size, generation of large defects, and formation of bound magnetic polarons. These Ag-doped ZnO thin flms are suitable for spintronics. Keywords Ag doping · Magnetic properties · Dielectric properties · Spintronics 1 Introduction Thin flms are propitious structures studied rather than the same bulk counterparts due to some encouraging factors like small size, less weight, strength, and to take the shape of substrates [1]. From the recent past, DMSs (diluted magnetic semiconductors) have become an interesting and attractive area of research due to their prospective applications in spintronic, memory devices, and quantum computers [3]. ZnO is one of the most encouraging DMS candidates due to its considerable semiconductor performance [4]. ZnO also possesses outstanding chemical stability and excel- lent piezoelectric property [5]. ZnO thin flms have been studied extensively for the last few decades. It is the most auspicious/propitious and important material in many areas. It has well-defned advantages such as inexpensive, abun- dant, safe in use, chemically stable, highly transparent in the visible and near-infrared spectral region [6] environmentally friendly, and highly catalytic [7]. It has a wide bandgap of 3.37 eV and having 60 meV exciton binding energy [8]. Due to the direct bandgap, ZnO has unique properties and it has the fexibility to be used in diferent applications such as LEDs, gas sensors, UV lasers transparent conductive flms, optoelectronics, solar cells, and window display due to its electric polarization behavior [9–12]. ZnO exhibits n-type conductivity due to oxygen vacancies and Zn +2 interstitials. However, it can attain P-type conductivity by doping and hence become promising in the research feld. Theoretical studies show that silver is a suitable dopant to attain P-type ZnO [13]. Doping with transition elements is the successful approach to modify optical, chemical, magnetic, and electri- cal properties of ZnO thin flms [14]. Among all transition metals, the silver is the most appropriate choice due to its solubility, it has one outermost electron that’s why it has a large ionic size and orbital energy [15]. Sliver is a naturally existing transition metal and among all chemical elements found in the earth’s crust, its abundance is 63rd in order [16]. In addition, Ag is an inexpensive, non-toxic, excellent elec- trical and high thermal conductor as compared to other tran- sition metal. The enhanced properties of ZnO doped with Ag are primarily due to hinder of trapping of photogenerated * Zohra Nazir Kayani zohrakayani@yahoo.com 1 Lahore College for Women University, Lahore 54000, Pakistan 2 Centre of Excellence in Solid State Physics, University of the Punjab, Lahore 54950, Pakistan