Spontaneous rotation of ferrimagnetism driven by antiferromagnetic spin canting*

Spin-reorientation phase transitions that involve the rotation of a crystal’s magnetisation have been well characterised in distorted perovskite oxides such as the orthoferrites. In these systems spin reorientation occurs due to competing rare earth and transition metal anisotropies coupled via f − d exchange. Here, we demonstrate an alternative paradigm for spin reorientation in distorted perovskites. We show that the R₂CuMnMn₄O₁₂ (R = Y or Dy) triple A-site columnar ordered quadruple perovskites have three ordered magnetic phases and up to two spin reorientation phase transitions. Unlike the spin reorientation phenomena in other distorted perovskites, these transitions are independent of rare earth magnetism, but are instead driven by an instability towards AFM spin canting originating in frustrated Heisenberg exchange interactions, and the competition between Dzyaloshinskii-Moriya and single-ion anisotropies.