Magnetic structure of the noncentrosymmetric magnet Sr2MnSi2O7 through irreducible representation and magnetic space group analyses

Magnetic structures of the noncentrosymmetric magnet Sr 2 MnSi 2 O 7 were examined through neutron diffraction for powder and single-crystalline samples, as well as magnetometry measurements. All allowed magnetic structures for space group P 4 2 1 m with the magnetic wavevector q m = (0, 0, ½) were refined via irreducible representation and magnetic space group analyses. The compound was refined to have in-plane magnetic moments within the magnetic space group Cmc 2 1 .1′ c (No. 36.177) under zero field, which can be altered to P 2 1 2 1 2 1 .1′ c (No. 19.28) above μ 0 H = 0.067 (5) T to align induced weak-ferromagnetic components within one layer on the ab plane. All refined parameters are provided following the recent framework based upon the magnetic space group, which better conveys when exchanging crystallographic information for commensurate magnetic structures.