Theoretical Calculations and Solid-Phase Synthesis of the Single Phase Multiferroic CaMn7O12

On theoretical aspect, The R (3) over bar crystal structure and the proper-screw magnetic order (the electronic structure and the transformation mechanisms) of CaMn7O12 were calculated by using the first principles calculation based on the density function theory. The purity-phase CaMn7O12 was prepared by solid reaction process according to the TG-DSC analysis in the experiment, which was known as a new single-phase multiferroic material, and its magnetic and electric properties were characterized successfully. Two magnetic phase transition temperature (T-N1=90 K and T-N2=45 K) and a hysteresis loop at 10 K (M-r= 0.02 emu . g(-1) and H-c approximate to 1 000 Oe) are measured by the magnetism performance testing. The electrical performance testing indicates that CaMn7O12 has the dielectric constant epsilon(r)=280 and the dielectric loss tan delta=1.69 at room temperature (at 10 MHz).