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In this paper, we present a comprehensive investigation of the distinctive magnetic properties involving the remarkable occurrences of negative magnetization (NM), exchange bias (EB), and spin reorientation (SR) in the ErFe₀. ₅Co₀. ₅O₃ compound. The dc magnetization data, recorded in field-cooled-cooling mode, reveal a net zero magnetization at the compensation temperature (T₂₎₌) of 24 K, leading to the NM phenomenon in the compound. Rietveld refinement of the neutron diffraction (ND) patterns over 1. 5--300 K elucidates the SR of Fe/Co spins at 100 K (Tₒₑ) and Er magnetic ordering 4 K (T₍^Er) resulting in ₄ (Gₗ), ₂₄ (Gₙ, Gₗ), ₂ (Gₙ), and ₂₅₇ (Gₙ;Aₘ^ErGₙ^Er) magnetic structures at T > Tₒₑ, TₒₑT₂₎₌, T₍^ErTT₂₎₌, and T0. 16em{0ex}0. 16em{0ex}T₍^Er, respectively. It is, therefore, evident that the SR of Fe/Co moments from ₄ (Gₗ) to ₂ (Gₙ) gets completed at the T₂₎₌ of 24 K, and the Er magnetic ordering into an unusual ₅₇ (Aₘ^ErGₙ^Er) spin configuration takes place at T4 K. Anomalies in dc magnetization data (coercivity and remanent magnetization) at Tₒₑ, T₂₎₌, and T₍^Er are also reflected in the ac susceptibility data. Intriguingly, EB field (H₄₁) in the compound does not change its polarity across T₂₎₌ and remains positive even above T₂₎₌. The observed positive H₄₁ at T > T₂₎₌ can be attributed to a complex spin arrangement as evident from the ND, whereas for T T₂₎₌, positive H₄₁ has its usual explanation within the framework of the Meiklejohn-Beam model. The maximum positive H₄₁ and a broad hump in H₄₁ at T₂₎₌ and Tₒₑ, respectively, indicate a correlation between the EB and SR in the compound. Additionally, cooling-field dependence of the EB shows a peak value 5 kOe; thereafter, an unusual suppression of H₄₁ up to 70 kOe cooling field is found. The observed NM below T₂₎₌ is elucidated using the Cooke's model, where the polarized Er moment, under the internal magnetic field of the ordered canted antiferromagnetic Fe/Co sublattice, competes with the ferromagnetic Fe/Co moment. This results in a complete cancellation of magnetization at T₂₎₌ and the emergence of NM below T₂₎₌ in the compound. The specific heat data reveal a Schottky anomaly, inferring the dominant polarized nature of the Er moment below T₂₎₌. In this paper, we underscore the pivotal role of Er and Fe/Co exchange coupling in shaping the intriguing and complex magnetic properties---NM and EB---of the compound. These findings highlight the potential utility of the compound in spintronic applications.
Garg et al. (Tue,) studied this question.