The oxides with perovskite structure possess abundant physical properties, such as magnetism, dielectricity, photoelectricity, ferroelectricity, etc. The oxygen ions in the perovskite unit cell constitute an octahedra...The oxides with perovskite structure possess abundant physical properties, such as magnetism, dielectricity, photoelectricity, ferroelectricity, etc. The oxygen ions in the perovskite unit cell constitute an octahedral distribution. The deformation or tilting of the special oxygen octahedra structure leads to new performances or properties change. Here, we give a review of the relationship between magnetic and electrical behaviors and oxygen octahedral tilting in several typical perovskite oxides. An understanding of how to tune these properties by controlling the tilting during the sample growth can more effectively guide the design of new structures for high performance and inspiring their potential applications.展开更多
In recent decades, magnetoelectric effect in multiferroic materials has attracted extensive attention owing to the upcoming demands for new-generation multi-functional magnetoelectronic devices, such as transducer, se...In recent decades, magnetoelectric effect in multiferroic materials has attracted extensive attention owing to the upcoming demands for new-generation multi-functional magnetoelectronic devices, such as transducer, sensor and so on. This gives people a strong push to explore the multiferroic materials with a reduced dimension and effective coupling between electric and magnetic orderings, especially at room temperature. Due to the weak magnetoelectric coupling strength in sing-phase multiferroic materials, scientists start to design nanocomposites and artificial nanostructures with strong coupling among order parameters(lattice, charge, spin and orbital). In this review, we will introduce recent major progresses of magnetoelectric coupling in multiferroic nanocomposites across their interfaces from the following four aspects: strain effect, charge transfer, magnetic exchange interaction and orbital hybridization, based on their coupling mechanisms. Through a full understanding of the above coupling among these orderings, it is possible to achieve the nanoscale modulation of magnetization(ferroelectric polarization) by external electric(magnetic) field. Apart from the magnetoelectric coupling, those artificially functional nanocomposites provide us a platform to explore and study the emerging physical phenomena so that we can design self-assembled nanostructures to tailor novel functionalities in future applications.展开更多
Two spatially confined La0.8Ca0.2MnO3（LCMO） microbridges with different widths, starting from a single LCMO fihn （3mm×5 mm）, are fabricated by optical lithography. A second new and robust metal-insulator tran...Two spatially confined La0.8Ca0.2MnO3（LCMO） microbridges with different widths, starting from a single LCMO fihn （3mm×5 mm）, are fabricated by optical lithography. A second new and robust metal-insulator transition （MIT） peak at about 75K appears, in addition to the normal MIT at 180 K observed in the standard LCMO film. When the two bridges are processed by currents of high densities, interesting reversible resistance jumps are excited only around the new peak. A stronger dependence of resistance jump on current excitation is found for the bridge with a smaller width. The temperature driven transition between new excited multiple metastable states are involved to explain the interesting low-temperature ultra-sharp jumps.展开更多
La0.7Ca0.3MnO3 (LCMO) films and La0.7Ca0.3MnO3/Gd0.7Ca0.3MnO3 (LCMO/GCMO) multilayers have been prepared by pulsed laser deposition. The microstructures of both systems were investigated by transmission electron micr...La0.7Ca0.3MnO3 (LCMO) films and La0.7Ca0.3MnO3/Gd0.7Ca0.3MnO3 (LCMO/GCMO) multilayers have been prepared by pulsed laser deposition. The microstructures of both systems were investigated by transmission electron microscopy (TEM). The main structure of the films and the multilayers was monoclinic with a unit cell of size 2ap x-2ap. x -2ap, where ap is the lattice constant of single perovskite crystal. The LCMO films were composed of three-dimension multitwinning domains, while the LCMO/GCMO multilayers showed two-domain structure. In LCMO/GCMO multilayers, LCMO layers were coherent with GCMO layers and the interfaces between LCMO and GCMO layers were free from mismatch dislocation, which resulted in highly strained multilayerd structures.展开更多
基金supported by the National Natural Science Foundation of China (51272121, 51221291, and 51328203)
文摘The oxides with perovskite structure possess abundant physical properties, such as magnetism, dielectricity, photoelectricity, ferroelectricity, etc. The oxygen ions in the perovskite unit cell constitute an octahedral distribution. The deformation or tilting of the special oxygen octahedra structure leads to new performances or properties change. Here, we give a review of the relationship between magnetic and electrical behaviors and oxygen octahedral tilting in several typical perovskite oxides. An understanding of how to tune these properties by controlling the tilting during the sample growth can more effectively guide the design of new structures for high performance and inspiring their potential applications.
基金supported by the National Natural Science Foundation of China (51322207 and 51332001)Beijing Natural Science Foundation (2132023)the Fundamental Research Funds for the Central Universities (2012LYB07)
文摘In recent decades, magnetoelectric effect in multiferroic materials has attracted extensive attention owing to the upcoming demands for new-generation multi-functional magnetoelectronic devices, such as transducer, sensor and so on. This gives people a strong push to explore the multiferroic materials with a reduced dimension and effective coupling between electric and magnetic orderings, especially at room temperature. Due to the weak magnetoelectric coupling strength in sing-phase multiferroic materials, scientists start to design nanocomposites and artificial nanostructures with strong coupling among order parameters(lattice, charge, spin and orbital). In this review, we will introduce recent major progresses of magnetoelectric coupling in multiferroic nanocomposites across their interfaces from the following four aspects: strain effect, charge transfer, magnetic exchange interaction and orbital hybridization, based on their coupling mechanisms. Through a full understanding of the above coupling among these orderings, it is possible to achieve the nanoscale modulation of magnetization(ferroelectric polarization) by external electric(magnetic) field. Apart from the magnetoelectric coupling, those artificially functional nanocomposites provide us a platform to explore and study the emerging physical phenomena so that we can design self-assembled nanostructures to tailor novel functionalities in future applications.
基金Supported by the National Natural Science Foundation of China under Grant Nos U1332205,11404169 and 11274153the Natural Science Foundation of Jiangsu Province under Grant No BK20140450the Huaian Science and Technology(Industry)Project under Grant No HAG2014043
文摘Two spatially confined La0.8Ca0.2MnO3（LCMO） microbridges with different widths, starting from a single LCMO fihn （3mm×5 mm）, are fabricated by optical lithography. A second new and robust metal-insulator transition （MIT） peak at about 75K appears, in addition to the normal MIT at 180 K observed in the standard LCMO film. When the two bridges are processed by currents of high densities, interesting reversible resistance jumps are excited only around the new peak. A stronger dependence of resistance jump on current excitation is found for the bridge with a smaller width. The temperature driven transition between new excited multiple metastable states are involved to explain the interesting low-temperature ultra-sharp jumps.
基金NAMCC under Grant86&715-014-0070 and NSFC under Grant 59601002 and59831020.
文摘La0.7Ca0.3MnO3 (LCMO) films and La0.7Ca0.3MnO3/Gd0.7Ca0.3MnO3 (LCMO/GCMO) multilayers have been prepared by pulsed laser deposition. The microstructures of both systems were investigated by transmission electron microscopy (TEM). The main structure of the films and the multilayers was monoclinic with a unit cell of size 2ap x-2ap. x -2ap, where ap is the lattice constant of single perovskite crystal. The LCMO films were composed of three-dimension multitwinning domains, while the LCMO/GCMO multilayers showed two-domain structure. In LCMO/GCMO multilayers, LCMO layers were coherent with GCMO layers and the interfaces between LCMO and GCMO layers were free from mismatch dislocation, which resulted in highly strained multilayerd structures.
