Probing structural transformation and optical and magnetic properties in Cr doped GdMnO3: Jahn–Teller distortion, photoluminescence and magnetic switching effect

Abstract

The systematic evolution of structure, photoluminescence and different magnetic transitions in GdMnO₃ is reported after Cr doping. With increasing the Cr concentration from 10 to 40 at%, Rietveld refinement of X-ray diffraction patterns demonstrates that an O′ type orthorhombic structure transforms to O type, manifesting a reduction in lattice volume. The noticeable reduction in lattice volume is ascribed to the smaller size of the Cr³⁺ ion compared to Mn³⁺. The structural transformation is accompanied with a considerable decrease in the Jahn–Teller distortion factor evaluated from XRD, Raman and photoluminescence measurements. Magnetic studies reveal a considerable enhancement in Néel temperature (T_N) from ∼42 K for x = 0 to 130 K for x = 0.4. Interestingly, we observe magnetization reversal (MR) with spin reorientation (TSR) for x = 0.3. The mechanism for such a magnetic behavior is discussed on the basis of competition between Mn, Cr and Gd. The incorporation of Cr not only constructively modifies the crystal structure and evokes the magnetic reversal phenomenon but also contributes towards the enhanced emission spectra. The promising structure and magnetic properties of Cr doped GdMnO₃ offer potential pathways for spintronics and magnetic switching devices.