Commensurate and incommensurate magnetic structure of the moderately frustrated antiferromagnet Li2M(WO4)2 with M = Co, Ni

We have investigated the magnetic structure of Li2Co(WO4)(2) via magnetic susceptibility, and neutron diffraction measurements. Two magnetic transitions are observed in magnetic susceptibility at T-N1 similar to 9.5 K and T-N2 similar to 7.2 K. Neutron diffraction reveals an incommensurate magnetic order with a wave vector k(ICM) = (similar to 0.46, similar to 0.27, similar to 0.24) between T-N1 and T-N2 and a commensurate magnetic order with a wave vector k(CM) = (0.5, 0.25, 0.25) below T-N2. The magnetic periodicity in the commensurate phase is four times larger than the nuclear unit cell length along the b- and c-axis directions with a saturated magnetic moment equal to approximate to 2.92 mu(B) . Below T-N1, the ICM wave vector for Li2Co(WO4)(2) varies with decreasing temperature and locked into commensurate at T-N2, whereas weaker temperature dependence of k(ICM) = (0.46, 0.17, 0.33) is observed for Li2Ni(WO4)(2).

Automated summary

The magnetic structure of Li2Co(WO4)(2) was investigated using magnetic susceptibility and neutron diffraction measurements. Two magnetic transitions were observed at T-N1 around 9.5 K and T-N2 around 7.2 K. The neutron diffraction showed an incommensurate magnetic order between T-N1 and T-N2, and a commensurate magnetic order below T-N2.