Temperature evolution of 3- and 4-electron magnetic ordering in the ferrimagnetic Mn self-doped perovskite (YbMn)MnO.

A high-pressure synthesis method was employed to prepare Mn-self-doped perovskites (Mn)MnO(= Yb, Lu) at about 6 GPa and 1670 K. Crystal and magnetic structures of (YbMn)MnOhave been studied by combining neutron powder diffraction, magnetic susceptibility and specific heat measurements. Within the orthorhombic space group, magnetic cations are located on site 4(A site, occupied by two thirds of Yband one third of Mn) and on site 4(B site, occupied by two thirds of Mnand one third of Mn). The degree of structural distortion of the MnOoctahedra follows the general trend of (RMn)MnOcompounds which shows a decrease with increasing amount of Jahn-Teller inactive Mncations. Mn-Mn interactions produce a collinear ferrimagnetic structure (= 106 K) with ferromagnetically ordered Mn moments at the B site being coupled antiferromagnetically with ordered Mn moments at the A site. Mn-Yb interactions induce a small but non-zero ferromagnetic Ybmoment which can explain a small decrease of the magnetic susceptibility at low temperature. Yb-Yb interactions create an antiferromagnetic structure at≈ 40 K. Ordered moments of the ferrimagnetic and antiferromagnetic structures are oriented perpendicular to each other within the-plane and Ybmoments contribute to both structures. The appearance of ordered Ybmoments induced by Mn-Yb interactions in perovskite (YbMn)MnOis a result of the Mn self-doping on the A site and has not been observed in the orthorhombic perovskite modification (space group) of the undoped parent compound YbMnO, but interestingly, it also appears in the hexagonal non-perovskite modification (space group6) of YbMnO.