Impact of gadolinium doping into the frustrated antiferromagnetic lithium manganese oxide spinel

Cubic spinel LiMn₂O₄ (LMO) are promising electrode materials for advanced technological devices owing to their rich electrochemical properties. Here, a series of Gd³⁺-doped LiMn₂O₄ were synthesized using a simple one-step sol-gel synthesis, and a systematized study on the effect of increasing Gd³⁺ concentration on magnetic properties is conferred. The Raman and density functional theory (DFT) calculations of the synthesized materials were correlated with the magnetic properties; we observed a high coercivity value for the doped LMO compared to pristine LMO, which scales down from 0.57T to 0.14T with an increase in Gd concentration. The samples exhibited paramagnetic (at 300K) to antiferromagnetic (at 5K) transition and variation in the magnetic moment due to the replacement of Mn⁺² or Mn⁺³ ion by Gd⁺³ ion from the octahedral 16d lattice site. The observed phase transitions in the hysteresis curve below the Neel temperature (T_N) at 5K are found to be due to the superexchange mechanism.