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Dielectric and magnetic properties of dilute magnetic semiconductors Ag‑doped ZnO thin films Zohra Nazir Kayani1   · Ayesha Usman2 · Hina Nazli1 · Riffat Sagheer1 · Saira Riaz2 · Shahzad Naseem2 Received: 9 March 2020 / Accepted: 22 June 2020 © Springer-Verlag GmbH Germany, part of Springer Nature 2020

Abstract Ag-doped ZnO thin films are prepared by the cost-effective 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 magnetic properties of ZnO are significantly 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 films has been recorded at room temperature. Magnetic polarons play a pivotal role in the development of room temperature ferromagnetism in Ag-doped ZnO thin films. So, ferromagnetism in thin films is governed by bound magnetic polarons. As the doping concentration increased, the saturation magnetization decreased and coercivity increased due to the combined effect of the decrease in crystallite size, generation of large defects, and formation of bound magnetic polarons. These Ag-doped ZnO thin films are suitable for spintronics. Keywords  Ag doping · Magnetic properties · Dielectric properties · Spintronics

1 Introduction Thin films 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 excellent piezoelectric property [5]. ZnO thin films have been studied extensively for the last few decades. It is the most auspicious/propitious and important material in many areas. It has well-defined advantages such as inexpensive, abundant, safe in use, chemically stable, highly transparent in the * Zohra Nazir Kayani [email protected] 1



Lahore College for Women University, Lahore 54000, Pakistan



Centre of Excellence in Solid State Physics, University of the Punjab, Lahore 54950, Pakistan

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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 flexibility to be used in different applications such as LEDs, gas sensors, UV lasers transparent conductive films, optoelectronics, solar cells, and window display due to its electric polar