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

Abstract

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 under the space group $P\bar{4}{2}_{1}m$ with the magnetic wavevector ${\vec{q}}_{\mathrm{m}}=(0,0,1/2)$~r.l.u., were analysed via irreducible representation and magnetic space group approaches. The compound is refined to have in-plane magnetic moments within the magnetic space group $Cmc{2}_1.1_c^{\prime }$ (\#36.177) under zero field, which can be altered to $P{2}_1{2}_1{2}_1.1_c^{\prime }$ (\#19.28) above $\hat{I}{¼}_{0}H=0.067(5)$~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.

7 pages, 4 figures