Role of high-temperature Fe/Mn-Er antiferromagnetic exchange coupling in spin transport at single crystal ErFe_0.55Mn_0.45O₃|Pt interface

A 3D AFM ErFe_0.55Mn_0.45O₃ (T_N = 355 K) exhibits antiferromagnetic (AFM) exchange coupling and interesting interplay between Fe/Mn and Er sublattices in Γ₄(G_x, A_y, F_z) phase at room temperature (T). For instance, lowering the T (under H = 50 Oe) first results in compensation point (zero net-magnetization, M_net) near 266 K and then exhibits negative M_net down to 255 K where it transforms to Γ₁(A_x, G_y, C_z) phase. Application of magnetic field (H) in Γ₄ phase changes the spin moment configuration wherein, M_net and Neel vector G_x tend to align parallel and perpendicular to H, respectively. Inside Γ₄ phase in ErFe_0.55Mn_0.45O₃, M_net is highly sensitive to the change in T and H. Here, we report spin Hall magnetoresistance (SMR) measurements carried out on b-plate of single crystal ErFe_0.55Mn_0.45O₃|Pt hybrid while rotating H in ac-plane. Our SMR studies in the T-range, 200 to 400 K probe Fe/Mn-Er AFM coupling, compensation point, negative magnetization and H-induced flipping of the sublattices, revealing the key role of competing relative magnitudes of Fe/Mn and Er sublattices (i.e. M_net) in the spin transport. In summary, our spin transport investigations on ErFe_0.55Mn_0.45O₃ underline prospects of this 3D AFM material at room temperature for future AFM spintronic devices.