Fig. 1. Ordered perovskite crystal structure (space group Im-3) of (A) A site of BiMn3Cr4O12 at room temperature, and (b) synchrotron radiation X-ray diffraction pattern. Figure 2. A series of magnetoelectric test results for BiMn3Cr4O12. (a) Magnetic Susceptibility and Curie-Weiss Law Fitting; (b) Specific Heat and Dielectric Constant; (c) Pyroelectricity and Electrode Intensity; (d) Magnetization Curve; (e) Low-Temperature Pyroelectricity (f) Low temperature electrode polarization. The magnetoelectric multiferroic material refers to a kind of multi-functional material with both magnetic ordering and electrodeposition order. By using two kinds of orderly coexistence and mutual coupling, the magnetic field can be controlled to be polarizable or the electric field can change magnetic properties. Multiferroic materials have been widely studied as spintronics material systems with important application prospects, and are expected to be used to implement next-generation information memory, adjustable microwave signal processors, and ultrasensitive magnetic sensors. According to the origin of the polarization, multiferroic materials can be divided into the first type of multi-iron and the second type of multi-iron. In the first type of multiferroic material, the ferroelectric polarization and the magnetic order have different origins, and thus the magnetoelectric coupling is small although the electrical polarization strength may be relatively large. The second type of multi-ferroic material electrode is caused by the special spin structure breaking the space inversion symmetry, so this type of material has a strong magnetoelectric coupling, unfortunately, the intensity of the electrode is often very weak. Practical applications require materials with large electrical polarization and strong magnetoelectric coupling effects, but this compatibility is difficult to exist in previous single-phase multiferroic materials. Therefore, the search for a single-phase multiferroic material with both excellent properties is an urgent and extremely challenging scientific problem. Recently, Long Youwen research team of the EX6 group of the Key Laboratory of Extreme Condition Physics at the Institute of Physics, Chinese Academy of Sciences/Beijing National Laboratory for Condensed Matter Physics used a unique high-temperature and high-pressure technique to prepare an ordered A-perovskite for the first time. The structure of the BiMn3Cr4O12 system, and rarely found that the single-phase material has both large polarization strength and strong magnetoelectric coupling effect. Previous studies have shown that in A-ordered perovskites of the chemical formula AA'3B4O12, transition metal ions are accommodated at both the A' and B sites, so the structure and magnetoelectric properties of the materials can be controlled by selecting suitable ion combinations. , thereby inducing magnetoelectric multiferroicity. Under the guidance of this idea, the researchers designed a new A-ordered perovskite material, BiMn3Cr4O12, and obtained this compound first under high-pressure and high-temperature experimental conditions of 8GPa and 1100C. Through a series of integrated structural characterizations and physical properties tests such as magnetic susceptibility, magnetization, specific heat, dielectric constant, electrode polarization, hysteresis loop, high resolution electron microscope, synchrotron X-ray diffraction and absorption spectroscopy, neutron diffraction, etc. Based on the first-principles theoretical calculations, the researchers conducted a detailed study of the system. As temperature decreases, BiMn3Cr4O12 undergoes a ferroelectric phase transition at 135K. Since the phase transition temperature accessory material has not yet formed a spin order, the ferroelectric phase transition has nothing to do with the magnetic ordering. Further X-ray refinement results and theoretical calculations of the low temperature synchrotron radiation show that the lone pair electronic effect of the Bi3+ ion is causing the Ferroelectric phase change causes. Below this ferroelectric phase transition temperature, significant hysteresis loops can be observed and lead to large polarisation intensities (2 orders of magnitude greater than the classic second-class multiferroic material). When the temperature is reduced to 125K, BiMn3Cr4O12 undergoes an anti-ferromagnetic phase transition, and neutron diffraction proves that the antiferromagnetic transition originates from the G-type long-range antiferromagnetic ordering of the Cr3+ ion at the B site and the Mn3+ ion at the A' position. Magnetic order has not yet been formed. Below 125K, long-range magnetic ordering coexists with the ferroelectric polarization, but the antiferromagnetic sequence cannot induce an electrical phase transition, so the material enters the first type of multiferroic phase with a large electrical polarization strength. When the temperature continues to decrease to 48K, the Mn3+ ion at the A′ position also achieves G-type long-range antiferromagnetic ordering, and the spin-ordered structure composed of the Mn3+ ion at the A′ position and the Cr3+ ion at the B position results in the polarized magnetic point. The formation of groups can break the symmetry of spatial inversion. Therefore, the antiferromagnetic phase transition at 48K induces another ferroelectric phase transition, with the appearance of a strong magnetoelectric coupling effect, at which time the material simultaneously exhibits a second type of multiferroic phase. It can be seen that BiMn3Cr4O12 contains both the first and second multiferroic phases at low temperatures, so that large polarization and strong magnetoelectric coupling effects are achieved simultaneously in this single-phase multiferroic material. In the past, these two effects were difficult to be compatible in single-phase materials, which promoted the potential application of multiferroic materials. The relevant research results were published on Advanced Materials and were selected as Inside Cover. The research work has won extensive cooperation with domestic and foreign counterparts. The theoretical calculations were done in cooperation with Professor Dong Shuai of Southeast University. The powder neutron diffraction was done in collaboration with Dr. H. Cao and S. Calder of Oak Ridge National Laboratory, USA. Synchrotron radiation X-ray diffraction and Y. Shimakawa, professor of Kyoto University, completed the cooperation. Electron microscopy research was done in collaboration with the research group of Professor M. Azuma of Tokyo Institute of Technology. Sun Yang, researcher at the Institute of Physics, Chinese Academy of Sciences, and Associate Researcher Shiyue Ii made a good discussion on the work. The research work was supported by the Ministry of Science and Technology, the National Natural Science Foundation of China, and the Chinese Academy of Sciences. Welded Wire Mesh Panels,Welded Wire Fence Panels,Welded Wire Panels,Wire Mesh Fence Panels ANPING HONGYU WIREMESH CO.,LTD , https://www.hongyufence.com
Figure 3. Hysteresis loops at different temperatures for BiMn3Cr4O12, demonstrating a large polarisation strength. 
Figure 4. The magnetic field modulates the polarization of BiMn3Cr4O12, demonstrating a strong magnetoelectric coupling effect. 
Figure 5. Magnetoelectric phase diagram of BiMn3Cr4O12 at different temperatures. PM = paramagnetic, PE = paraelectric, FE = ferroelectric, MF = multiferroic.