Magnetic ordering in Ce substituted zirconite-YCrO₄ nanostructures: focus on tunable energy bandgap and local-atomic environment

Abstract

We present a meticulous study on the structural, magnetic, electronic and optical spectroscopic analysis of tetragonal Zirconite Y1-xCexCrO4. Pristine system YCrO4 exhibits ferromagnetic (FM) ordering with Curie temperature, TC ~ 9.3 K. However, with the substitution of magnetic Ce3+ at Y sites leads to decrease in TC and emergence of weak antiferromagnetic (AFM) character as evident from the negative Curie-Weiss temperature (-10≲θCW≲-30). We find that moderate substitution of Ce results large thermal irreversibilities in the field-cooled (FC) and zero-field-cooled (ZFC) magnetization ΔM ( FC− ZFC) providing the signatures of high magneto-crystalline anisotropy. Field dependent magnetization data exhibits higher saturation magnetization values ( MS ≳ (2.7 − 4.4) × 103 emu/mole) and higher magneto-crystalline anisotropy (K1 ~ 2.18−3.41 J/m3) for x≤0.05. Local atomic environment probed by the electron spin resonance clearly indicate the presence of hyperfine splitting of Cr5+spectra having single d-electron ( 21 0) with orbital configuration bearing the possible doublet: F= 1,2 (I=3/2, J=1/2). However, Ce3+ spectra show hyperfine-doublets as 7/2 and 9/2. The energy band-gap (Eg= 2.14-2.38 eV, for x ~ 0-0.1) determined from the diffuse reflectance spectroscopy reveals the emergence of intermediate localized states upon substitution of Ce3+.