TY  - JOUR
AU  - Dutta, Rajesh
AU  - Thoma, Henrik
AU  - Sazonov, Andrew
AU  - Náfrádi, Bálint
AU  - Meven, Martin
AU  - Gukasov, Arsen
AU  - Kocsis, Vilmos
AU  - Zeitler, Uli
AU  - Puri, Alessandro
AU  - Tokunaga, Yusuke
AU  - Taguchi, Yasujiro
AU  - Tokura, Yoshinori
AU  - Bordács, Sándor
AU  - Kézsmárki, István
AU  - Hutanu, Vladimir
TI  - Magnetic structure of the two-dimensional XY antiferromagnet Sr$_2$CoSi$_2$O$_7$ studied using single-crystal neutron diffraction
JO  - Physical review / B
VL  - 107
IS  - 1
SN  - 2469-9950
CY  - Woodbury, NY
PB  - Inst.
M1  - FZJ-2023-04487
SP  - 014420
PY  - 2023
AB  - We report a combined polarized and unpolarized neutron diffraction study on a multiferroic Sr$_2$CoSi$_2$O$_7$ (SCSO) single crystal below and above the antiferromagnetic ordering temperature $T_N$ = 6.5 K. Unpolarized neutron diffraction measurements at 15 K confirm the melilite-type tetragonal $P\overline{4}2_1m$ space group as the parent structure of SCSO. The low temperature study at 2.3 K, in contrast, reveals symmetry lowering with the orthorhombic Cmm′2′ and $P2_12′_12′$ magnetic space groups being equally possible. In these $Cmm′2′$ and $P2_12′_12′$ magnetic space groups we obtain a very similar ordered magnetic moment about 2.86 and 2.94μB/Co$^{2+}$, respectively, which lies in the $ab$ plane. Our spin polarized flipping ratio measurements under an applied magnetic field of 6 T in the paramagnetic state support the results of our bulk magnetization data, indicating strong easy-plane spin anisotropy, responsible for the in-plane order below $T_N$.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000927608900003
DO  - DOI:10.1103/PhysRevB.107.014420
UR  - https://juser.fz-juelich.de/record/1018017
ER  -