Magnetic structure and magnetoelectric effect in the centrosymmetric antiferromagnet Cu2⁢(MoO4)⁢(SeO3)

Magnetic properties of Cu2⁢(MoO4)⁢(SeO3), an S = 1/2 centrosymmetric antiferromagnet (AFM), were investigated using superconducting quantum interference device magnetometry, neutron diffraction, and magnetoelectric (ME) measurements. The magnetic susceptibility measurements indicate a broad peak at ∼50 K, followed by a phase transition into AFM order at 𝑇N=23.6⁢(1) K. Above 𝑇N, a fit to the Curie-Weiss law gives a Curie-Weiss temperature ΘCW=−68⁢(1) K, suggesting the dominant AFM coupling. Neutron powder diffraction reveals that the C⁢u2+ spins are aligned AFM along the 𝑐 axis with weak noncollinearity under the magnetic space group of P2′1/𝑐. The ME response indicates that a nondiagonal component of a ME tensor is active, supporting the simultaneous spatial and time reversal symmetry breaking under P2′1/𝑐.