Effects of Cr-doping concentration on the structural, optical, and magnetic properties of ZnO thin films

Abstract

Cr-doped ZnO thin films have been prepared on silicon (100) substrates by a radio-frequency (RF) magnetron sputtering method. The crystallographic structures, optical, and magnetic properties of the thin films are investigated by means of X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), photoluminescence (PL), and physical properties measurement system (PPMS), respectively. The XPS results confirm that the chemical-bonding state of the doped Cr ions is þ3. XRD analyses reveal that the Cr ions successfully replace Zn atoms and incorporate into the crystal-lattice positions of ZnO.Magnetic measurements reveal that all the samples have ferromagnetic features and saturation magnetization increases on increasing the dopant concentration. Room-temperature PL spectra show an ultraviolet (UV) emission at 380 nm and a green emission at 500 nm, whose intensity is greatly increased with increased Cr dopant. Moreover, the results of PL further testify that ferromagnetism (FM) is an intrinsic property of the Cr-doped ZnO films and FM can be described by bound magnetic polaron (BMP) models with respect to defect-bound carriers.

Multiferroic Properties and Magnetoelectric Coupling of Fe‐Doped (Ba0.7Ca0.3)TiO3‐Ba(Zr0.2Ti0.8)O3 Ceramics

“…For BCZTF x , Fe 3+ ions (0.645 Å) enter into B‐site as its ion radius is very close to that of Ti 4+ (0.605 Å) but much smaller than that of Ba 2+ (1.61 Å) or Ca 2+ (1.34 Å), which thus results in the presence of oxygen vacancies due to the requirement of charge balance. The exchange coupling between the bound electrons from oxygen vacancies and Fe 3+ ions can form the bound magnetic polarons . As shown in Figure , the bound electrons occupy Bohr orbit, and as a bound polaron, which can control the spins of Fe 3+ ions within its volume and form local magnetic moment.…”

Structural and optical properties of Cr-doped ZnO thin films

“…The change in the direction of strain can be attributed to the broadening of the peak with increase in the chromium doping concentration. 15 The decrease in grain size with chromium concentration for the films deposited on silicon substrate by using the RF sputtering method was also reported by Fu et al 12 The lattice parameters a = b, c and bond length (l) for the hexagonal wurtzite structure were also estimated from XRD data by using the well-known expressions. 16,17 Variation in these parameters with different chromium doping concentrations is plotted in Figure 3 zinc oxide:chromium thin film.…”

“…10 Most researchers reported the structural, optical and magnetic properties of chromium-doped zinc oxide powder and thin films. [8][9][10][11][12] The sol-gel spin-coating technique is a simpler, easier and cost-effective method to obtain thin films with the easy control of compositions.…”

Synthesis and magnetic properties of the chromium-doped iron sulfide Fe1−xCrxS single crystalline nanoplates with a NiAs crystal structure

“…15 Cr doping can also significantly change the magnetic properties of the material. 17 In Mn 1Àx Cr x As (NiAs-type structure), lowering of the firstorder transition temperature from 313 to 265 K was observed with increasing Cr concentration x from 0.006 to 0.01. 16 Moreover, the enhancement of T C value from 175 to 250 K was found at x = 0.27.…”