STRUCTURAL, OPTICAL, AND PARAMAGNETIC INVESTIGATIONS OF (Mn2+) IONS DOPED ZINCALUMINOBOROPHOSPHATE (ZnAlBP) GLASS SYSTEM

Abstract

Concentration variation of Mn2+ ions doped zincaluminoborophosphate (ZnAlBP) glasses of 40 ZnO + 25 H3BO3 + (30-x) P2O5 + 5 Al2O3 + x MnO with 0  x  0.8 (x=0, 0.2, 0.4, 0.6 and 0.8) have been prepared and investigated by structural and spectroscopic techniques. The XRD diffractograms confirm the amorphous nature of the prepared samples. The FTIR spectra reveal the existence of BO3 and BO4 units along with fundamental P-O-H and B-O-H structural units in the present glass system. The Optical absorption spectra exhibit two low intensity bands centered at 407 nm (24,570 cm-1) and 689 (14,514 cm-1). These bands were assigned to 6A1g(S) → 4A1g (G) + 4Eg (G) and6A1g(S) → 4T1g (G) characteristic transitions of Mn2+ ions in octahedral symmetry. Tauc’s plots were drawn to measure the optical band gaps for the direct and indirect transitions. The energy gaps show a decreasing trend for the selected ZnAlBP: Mn2+ glass system. The well-resolved hyperfine splitting EPR spectra of prepared glass samples exhibit resonance at g ≈ 1.98 indicating the Mn2+ ions are in octahedral site symmetry. The hyperfine splitting factor (hfs), the number of spin levels (N), hyperfine constant (A), zero-field splitting parameter (D), and paramagnetic susceptibility (χ) have been determined. The magnitude of g indicates the predominant ionicity in the glasses.