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ARTICLE

Room Temperature Ferromagnetism and Enhanced DC Conductivity in Cd_0.9Cr_0.1S Nanocrystalline Thin Films

Nourah A. Alsobai¹, Norah Alsairy², A. Ashour³, A. M. Ismail⁴, Khaled M. Abdelbased⁵, Atef Ismail^6,*

1 Department of Physics, College of Science, Taif University, Taif, Saudi Arabia
2 Department of Physics, College of Turabah, Taif University, Taif, Saudi Arabia
3 Physics Department, Faculty of Science, Islamic University of Madinah, Madinah, Saudi Arabia
4 Department of Physics, College of Science, Qassim University, Buraidah, Saudi Arabia
5 Unit of Scientific Research, Applied College, Qassim University, Buraidah, Saudi Arabia
6 Physics Department, Al-Azhar University, Asyut, Egypt

* Corresponding Author: Atef Ismail. Email:

(This article belongs to the Special Issue: Chalcogenide Thin Films and Solar Cells for Optoelectronic Applications)

Chalcogenide Letters 2026, 23(6), 1 https://doi.org/10.32604/cl.2026.083101

Received 29 March 2026; Accepted 25 May 2026; Issue published 02 July 2026

Abstract

This study presents a comparative investigation of the structural, DC electrical, and magnetic properties of pure cadmium sulfide (CdS) and 10% chromium-doped CdS (Cd_0.9Cr_0.1S) nanocrystalline thin films deposited by thermal evaporation. X-ray diffraction analysis confirmed the polycrystalline hexagonal (wurtzite) structure of both films with no detectable secondary phases. Upon Cr doping, the full width at half maximum (FWHM) of the principal diffraction peaks increased systematically, leading to a reduction in average crystallite size from 19.8 nm to 13.9 nm, accompanied by an increase in lattice strain (from 2.48 to 3.52) × 10⁻³ and dislocation density (from 2.55 to 5.17 line/nm²) × 10⁻³. Temperature-dependent DC conductivity measurements revealed thermally activated conduction in both films, following the Arrhenius relation. Chromium doping significantly reduced the activation energy from 0.43 eV to 0.30 eV and enhanced room temperature conductivity by approximately three orders of magnitude (from 8.3 × 10⁻⁷ S/cm to 3.4 × 10⁻⁴ S/cm), attributed to the introduction of impurity states and increased carrier concentration. Most notably, magnetic measurements demonstrated a clear transition from diamagnetic behavior in pure CdS to well-defined room-temperature ferromagnetism in the (CdS)_0.9Cr_0.1 film, with saturation magnetization (M_s) of 1.11 emu/cm³, remanent magnetization (M_r) of 0.31 emu/cm³, and coercivity (H_c) of 220 Oe. The observed ferromagnetism is explained by carrier-mediated exchange interactions through bound magnetic polaron formation, supported by the high density of structural defects and localized states. The combination of enhanced electrical transport and room-temperature ferromagnetic ordering positions Cr-doped CdS thin films as promising candidates for spintronic and optoelectronic device applications.

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