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
Mg0.2Zn0.8OMZO/La0.67Ca0.33MnOLCMO heterostructure was deposited on p-^＋-Si substrates by sol-gel spin coating technique. The Ag/MZO/LCMO/p-^＋-Si devices exhibit a bipolar, reversible, and remarkable current-voltage...Mg0.2Zn0.8OMZO/La0.67Ca0.33MnOLCMO heterostructure was deposited on p-^＋-Si substrates by sol-gel spin coating technique. The Ag/MZO/LCMO/p-^＋-Si devices exhibit a bipolar, reversible, and remarkable current-voltage characteristic at room temperature. An obvious multilevel resistive switching effect is observed in the devices. The dominant conduction mechanism of the devices is trap-controlled space charge limited current. The resistance ratio of high resistance state and low resistance state of the devices is about six orders of magnitude, and the degradation is invisible in the devices after 250 successive switching cycles. The present results suggest that the Ag/MZO/LCMO/p-^＋-Si devices may be a potential and multilevel candidate for nonvolatile memory application.展开更多
文摘采用磁控溅射法在STO(001)基片上沉积钙钛矿结构LCMO薄膜,研究了退火温度对LCMO薄膜微结构及电输运特性的影响.研究结果表明,随退火温度的升高,薄膜中氧含量及Mn4+/Mn3+比逐渐升高,LCMO薄膜中的Mn4+/Mn3+比与薄膜中的氧含量有关,当氧含量增大时,Mn4+/Mn3+比相应增大.LCMO薄膜的电阻率随退火温度升高而逐渐减小,而LCMO薄膜的金属-绝缘相变温度随退火温度升高而逐渐升高,经850℃退火处理的LCMO薄膜的金属-绝缘相变温度可达257 K.
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.
基金Funded by the National Natural Science Foundation of China(No.51262003)the Guangxi Key Laboratory of Information Materials(Guilin University of Electronic Technology),China(No.1110908-10-Z)
文摘Mg0.2Zn0.8OMZO/La0.67Ca0.33MnOLCMO heterostructure was deposited on p-^＋-Si substrates by sol-gel spin coating technique. The Ag/MZO/LCMO/p-^＋-Si devices exhibit a bipolar, reversible, and remarkable current-voltage characteristic at room temperature. An obvious multilevel resistive switching effect is observed in the devices. The dominant conduction mechanism of the devices is trap-controlled space charge limited current. The resistance ratio of high resistance state and low resistance state of the devices is about six orders of magnitude, and the degradation is invisible in the devices after 250 successive switching cycles. The present results suggest that the Ag/MZO/LCMO/p-^＋-Si devices may be a potential and multilevel candidate for nonvolatile memory application.
