Non-collinear magnetic structure of manganese quadruple perovskite CdMn(7)O(12)

We report on the magnetic structure of CdMn(7)O(12) determined by powder neutron diffraction. We were able to measure the magnetic structure of this Cd containing and highly neutron absorbing material by optimizing the sample geometry and by blending the CdMn(7)O(12) with Aluminum powder. Below its Néel temperature T(N1) all magnetic reflections can be indexed by a single commensurate propagation vector k = (0, 0, 1). This is different to the case of CaMn(7)O(12) where the propagation vector is incommensurate and where an in-plane helical magnetic structure has been found. We observe a commensurate non-collinear magnetic structure in CdMn(7)O(12) with in-plane aligned magnetic moments resembling the ones in CaMn(7)O(12). However, the commensurate propagation vector prevents the appearance of a helical magnetic structure in CdMn(7)O(12). Finally, we also observe a third structural phase transition below ~60 K that can be attributed to phase separation.