An unexpected gap: Magnetic structures of La2O3(Fe1-xMnx)2Se2La2O3(Fe1-xMnx)2Se2 investigated by neutron diffraction and physical property measurements

We prepared a solid solution of La2O3(Fe1-xMnx)2Se2La2O3(Fe1-xMnx)2Se2 and performed elastic neutron diffraction experiments at 2 K, measured the magnetization from 2 to 300 K at 500 Oe and 10 T, and also performed resistivity measurements for selected samples. Our experiments show that atomic disorder and magnetic competition open a gap in the magnetic transition from the AFM3 order (x<0.1x<0.1) to the AFM1 order (x⩾0.3x⩾0.3) while the transition from AFM1xAFM1x (0.30.9x>0.9) appears to be seamless. The compositions at 0.10