Magnetic Structure of SrCo3P4O14 Determined from Neutron Powder Diffraction Results

The spin system in SrCo 3 P 4 O 14 was reported to be a $J_{1}$--$J_{1}$--$J_{2}$ trimerized spin-3/2 chain. The $J_{1}$ and $J_{2}$ exchange interactions were antiferromagnetic and ferromagnetic, respectively. However, in spite of expectation for the trimerized spin chain, a 1/3 quantum magnetization plateau does not appear. To investigate the sign of exchange interactions, we determined the magnetic structure using neutron powder diffraction measurements. Both the $J_{1}$ and $J_{2}$ exchange interactions are ferromagnetic. The previously reported spin system is incorrect. Therefore, no 1/3 quantum magnetization plateau exists.