A remarkable CER(colossal electroresistance) effect was observed in a series of polycrystalline Nd0.67Sr0.33MnO3 samples synthe-sized by high energy ball milling successive heat treatment.The CER ratio increased with ...A remarkable CER(colossal electroresistance) effect was observed in a series of polycrystalline Nd0.67Sr0.33MnO3 samples synthe-sized by high energy ball milling successive heat treatment.The CER ratio increased with increasing heating time and reached 3580% at a low temperature for the Nd0.67Sr0.33MnO3 ceramic annealed up to 13 h as measuring current was enhanced from 5 to 500 μA.The result showed that the CER effect was strongly dependent on the sample s microstructure,especially on the foreign phases whi...展开更多
Using pulsed laser deposition, Fex-C1-x films on Si (100) substrates were prepared. At T=300 K and B=5 T a large positive MR of 138% was found in Fe0.011-C0.989 film. It is also found that when T<258 K, the MR of F...Using pulsed laser deposition, Fex-C1-x films on Si (100) substrates were prepared. At T=300 K and B=5 T a large positive MR of 138% was found in Fe0.011-C0.989 film. It is also found that when T<258 K, the MR of Fe0.011-C0.989 film is negative and when 258 K<T<340 K, the MR of the film is positive. The MR of the material is also found to be controlled by the measuring current and measuring voltage. When B=2000 Oe, the MR is 11.5% at 2.5 mA and is 35% at about 35 V. The material has also a giant electroresistance of 500% at 8 V.展开更多
The interface with a pinned dipole within the composite barrier in a ferroelectric tunnel junction（FTJ） with symmetric electrodes is investigated.Different from the detrimental effect of the interface between the el...The interface with a pinned dipole within the composite barrier in a ferroelectric tunnel junction（FTJ） with symmetric electrodes is investigated.Different from the detrimental effect of the interface between the electrode and barrier in previous studies,the existence of an interface between the dielectric SrTiO_3 slab and ferroelectric BaTiO_3 slab in FTJs will enhance the tunneling electroresistance（TER） effect.Specifically,the interface with a lower dielectric constant and larger polarization pointing to the ferroelectric slab favors the increase of TER ratio.Therefore,interface control of high performance FTJ can be achieved.展开更多
Oxygen deficient Nd_(0.67)Sr_(0.33)MnO_(3-δ) ceramic samples were prepared using conventional ceramic technology.A colossal electroresistance(CER)effect was found in Nd_(0.67)Sr_(0.33)MnO_(3-δ) series.The electrical...Oxygen deficient Nd_(0.67)Sr_(0.33)MnO_(3-δ) ceramic samples were prepared using conventional ceramic technology.A colossal electroresistance(CER)effect was found in Nd_(0.67)Sr_(0.33)MnO_(3-δ) series.The electrical transport is magnetically coupled and spin-dependent over grain or phase boundaries.Electrical-field-induced changes of the spin array orientations inside of and between the magnetic domains by grain or phase boundaries have to be concluded for the strong electroresistive effect in Nd_(0.67)Sr_(0.33)MnO_(3-δ) series.展开更多
The electroresistance（ER） of La_（0.36）Pr_（0.265）Ca_（0.375）MnO_3（LPCMO） epitaxial thin film was studied under various dc currents.The current effect was compared for the unpatterned film and patterned microbr...The electroresistance（ER） of La_（0.36）Pr_（0.265）Ca_（0.375）MnO_3（LPCMO） epitaxial thin film was studied under various dc currents.The current effect was compared for the unpatterned film and patterned microbridge with a width of 50 μm.The value of ER in the unpatterned LPCMO film could reach 0.54 under a 1-mA current,which is much higher than ER under 1 mA for the patterned weak phase-separated La_（0.67）Ca_（0.33）MnO_3 and La_（0.85）Sr_（0.15）MnO_3 microbridges with 50-μm width.More interestingly,for the patterned LPCMO microbridge,the maximum of ER can reach 0.6 under a small current of 100 μ.A.The results were explained by considering the coexistence of ferromagnetic metallic phase with the charge-ordered phase,and the variation of the phase separation with electric current.展开更多
Orientation anisotropy is a well-known essential character for polarization characteristics of ferroelectric materials,which has been widely investigated in conventional ferroelectric random access memories.In this wo...Orientation anisotropy is a well-known essential character for polarization characteristics of ferroelectric materials,which has been widely investigated in conventional ferroelectric random access memories.In this work,we study the effects of orientation on the tunneling electroresistance(TER)of ferroelectric tunnel junctions(FTJs).Rhombohedral Pb(Zr_(0.7),Ti_(0.3))O_(3)(PZT)that has the polar axis along the(111)orientation is adopted as potential barriers and two kinds of FTJs that are composed of(001)-and(II1)-oriented PZT barriers and Nb:SrTiO_(3)(Nb:STO)electrodes,respectively,are fabricated.The(111)-oriented P1PZT/Nb:STO FTJ exhibits a giant ON/OFFratio of~1.9×10^(5),about 30 times that of the(001)-oriented device,due to the lowered PZT barrier in the ON state and the widen Schottky barrier in the OFF state based on current and capacitance analyses.In addition,compared to the(001)-oriented device,the(111)-oriented FTJ shows a sharper and faster switching between the ON and OFF states according to the nucleation-limited-switching dynamics model,giving rise to good linearity in memristive behaviors for synaptic plasticity and reliable retention and endurance properties for the resistance switching.The improved TER properties are ascribed to larger effective polarizations and 180°switching in the(111)-oriented PZT barrier.These results facilitate the design and fabrication of high-performance FTJ devices with the optimization of crystallographic orientation and polarization switching characteristics.展开更多
We report that fully transparent resistive random access memory （TRRAM） devices based on ITO/TiO2/ITO sandwich structure, which are prepared by the method of RF magnetron sputtering, exhibit excellent switching stab...We report that fully transparent resistive random access memory （TRRAM） devices based on ITO/TiO2/ITO sandwich structure, which are prepared by the method of RF magnetron sputtering, exhibit excellent switching stability. In the visible region （400 800 nm in wavelength） the TRRAM device has a transmittance of more than 80%. The fabricated TRRAM device shows a bipolar resistance switching behaviour at low voltage, while the retention test and rewrite cycles of more than 300,000 indicate the enhancement of switching capability. The mechanism of resistance switching is further explained by the forming and rupture processes of the filament in the TiO2 layer with the help of more oxygen vacancies which are provided by the transparent ITO electrodes.展开更多
We report an investigation into the magnetoresistance(MR)of La_(0.8)Ba_(0.2)MnO_(3)ultrathin films with various thicknesses.While the 13 nm-thick film shows the commonly reported negative magnetoresistive effect,the 6...We report an investigation into the magnetoresistance(MR)of La_(0.8)Ba_(0.2)MnO_(3)ultrathin films with various thicknesses.While the 13 nm-thick film shows the commonly reported negative magnetoresistive effect,the 6 nm-and 4 nm-thick films display unconventional positive magnetoresistive(PMR)behavior under certain conditions.As well as the dependence on the film's thickness,it has been found that the electrical resistivity and the PMR effect of the thinner films are very dependent on the test current.For example,the magnetoresistive ratio of the 4 nm-thick film changes from+46%to-37%when the current is increased from 10 nA to 100 nA under 15 kOe at 40 K.In addition,the two thinner films present opposite changes in electrical resistivity with respect to the test current,i.e.,the electroresistive(ER)effect,at low temperatures.We discuss the complex magnetoresistive and ER behaviors by taking account of the weak contacts at grain boundaries between ferromagnetic metallic(FMM)grains.The PMR effect can be attributed to the breaking of the weak contacts due to the giant magnetostriction of the FMM grains under a magnetic field.Considering the competing effects of the conductive filament and local Joule self-heating at grain boundaries on the transport properties,the dissimilar ER effects in the two thinner films are also understandable.These experimental findings provide an additional approach for tuning the magnetoresistive effect in manganite films.展开更多
Strontium doped perovskite-type Nd0.7Sr0.3MnO3 ceramics were synthesized completely by high-energy ball milling raw oxides of Nd2O3, SrCO3 and MnO2. The optimal ball milling time and mass ratio of milling balls to raw...Strontium doped perovskite-type Nd0.7Sr0.3MnO3 ceramics were synthesized completely by high-energy ball milling raw oxides of Nd2O3, SrCO3 and MnO2. The optimal ball milling time and mass ratio of milling balls to raw materials are 4 h and 10：1, respectively. The grain size of as-milled Nd0.7Sr0.3MnO3 ceramics ranges from 51 to 93 nm, and the fine particles contain two phases of crystalline phase and amorphous phase. For the Nd0.7r0.3MnO3 synthesized by ball milling and sequent heat treatment, a remarkable colossal electroresistance （CER） effect is observed and the CER ratio reaches 900% at Curie temperature Tc when the load voltage increases from 0.1 to 0.8 V.展开更多
Modulation between optical and ferroelectric properties was realized in a lateral structured ferroelectric CuInP_(2)S_(6)(CIPS)/semiconductor MoS_(2) van der Waals heterojunction.The ferroelectric hysteresis loop area...Modulation between optical and ferroelectric properties was realized in a lateral structured ferroelectric CuInP_(2)S_(6)(CIPS)/semiconductor MoS_(2) van der Waals heterojunction.The ferroelectric hysteresis loop area was modulated by the optical field.Two types of photodetection properties can be realized in a device by changing the ON and OFF states of the ferroelectric layer.The device was used as a photodetector in the OFF state but not in the ON state.The higher tunnelling electroresistance(~1.4×10^(4))in a lateral structured ferroelectric tunnelling junction was crucial,and it was analyzed and modulated by the barrier height and width of the ferroelectric CIPS/semiconductor MoS_(2) Schottky junction.The new parameter of the ferroelectric hysteresis loop area as a function of light intensity was introduced to analyze the relationship between the ferroelectric and photodetection properties.The proposed device has potential application as an optoelectronic sensory cell in the biological nervous system or as a new type of photodetector.展开更多
Although the basic concept was proposed only about 10 years ago,multiferroic tunnel junctions(MFTJs)with a ferroelectric barrier sandwiched between two ferromagnetic electrodes have already drawn considerable interest...Although the basic concept was proposed only about 10 years ago,multiferroic tunnel junctions(MFTJs)with a ferroelectric barrier sandwiched between two ferromagnetic electrodes have already drawn considerable interests,driven mainly by its potential applications in multi-level memories and electric field controlled spintronics.The purpose of this article is to review the recent progress of all-perovskite MFTJs.Starting from the key functional properties of the tunneling magnetoresistance,tunneling electroresistance,and tunneling electromagnetoresistance effects,we discuss the main origins of the tunneling electroresistance effect,recent progress in achieving multilevel resistance states in a single device,and the electrical control of spin polarization and transport through the ferroelectric polarization reversal of the tunneling barrier.展开更多
We report here studies on the influence of oxygen pressure on the electroresis-tance behavior of La0.9Sr0.1MnO3 thin films fabricated by laser molecular beam epi-taxy.It was found that the film deposited at lower oxyg...We report here studies on the influence of oxygen pressure on the electroresis-tance behavior of La0.9Sr0.1MnO3 thin films fabricated by laser molecular beam epi-taxy.It was found that the film deposited at lower oxygen pressure shows larger c-axis parameter,higher resistance,and more distinct electroresistance.These results reveal that the electroresistance of manganite thin films can be tuned by the conditions of film fabrication.展开更多
基金supported by the National Natural Science Foundation of China (10774040 and 10911120055/A0402)the Program for New Century Excellent Talents in University (NCET-08-0674)the Special Foundation for Young Scientists of Educational Commission of Hubei Province (Q200710008)
文摘A remarkable CER(colossal electroresistance) effect was observed in a series of polycrystalline Nd0.67Sr0.33MnO3 samples synthe-sized by high energy ball milling successive heat treatment.The CER ratio increased with increasing heating time and reached 3580% at a low temperature for the Nd0.67Sr0.33MnO3 ceramic annealed up to 13 h as measuring current was enhanced from 5 to 500 μA.The result showed that the CER effect was strongly dependent on the sample s microstructure,especially on the foreign phases whi...
基金This work was financially supported by the Ministry of Science and Technology of China (No. 2002CB613500) and National Natural Science Foundation of China (No. 50271034, No. 90401013).
文摘Using pulsed laser deposition, Fex-C1-x films on Si (100) substrates were prepared. At T=300 K and B=5 T a large positive MR of 138% was found in Fe0.011-C0.989 film. It is also found that when T<258 K, the MR of Fe0.011-C0.989 film is negative and when 258 K<T<340 K, the MR of the film is positive. The MR of the material is also found to be controlled by the measuring current and measuring voltage. When B=2000 Oe, the MR is 11.5% at 2.5 mA and is 35% at about 35 V. The material has also a giant electroresistance of 500% at 8 V.
基金supported by the National Natural Science Foundation of China(Grant No.11274054)the Open Project of Jiangsu Provincial Laboratory of Advanced Functional Materials,China(Grant No.12KFJJ005)
文摘The interface with a pinned dipole within the composite barrier in a ferroelectric tunnel junction（FTJ） with symmetric electrodes is investigated.Different from the detrimental effect of the interface between the electrode and barrier in previous studies,the existence of an interface between the dielectric SrTiO_3 slab and ferroelectric BaTiO_3 slab in FTJs will enhance the tunneling electroresistance（TER） effect.Specifically,the interface with a lower dielectric constant and larger polarization pointing to the ferroelectric slab favors the increase of TER ratio.Therefore,interface control of high performance FTJ can be achieved.
基金Project supported by the National Natural Science Foundation of China(10774040)Excellent Young Scientist Foundation of Hubei Province(2006ABB032)
文摘Oxygen deficient Nd_(0.67)Sr_(0.33)MnO_(3-δ) ceramic samples were prepared using conventional ceramic technology.A colossal electroresistance(CER)effect was found in Nd_(0.67)Sr_(0.33)MnO_(3-δ) series.The electrical transport is magnetically coupled and spin-dependent over grain or phase boundaries.Electrical-field-induced changes of the spin array orientations inside of and between the magnetic domains by grain or phase boundaries have to be concluded for the strong electroresistive effect in Nd_(0.67)Sr_(0.33)MnO_(3-δ) series.
基金Project supported by the National Natural Science Foundation of China(Grant No.11604010)the Fundamental Research Funds for the Central Universities,China(Grant No.FRF-TP-15-097A1)the Open Research Fund Program of the State Key Laboratory of Low-Dimensional Quantum Physics,China(Grant No.KF201611)
文摘The electroresistance（ER） of La_（0.36）Pr_（0.265）Ca_（0.375）MnO_3（LPCMO） epitaxial thin film was studied under various dc currents.The current effect was compared for the unpatterned film and patterned microbridge with a width of 50 μm.The value of ER in the unpatterned LPCMO film could reach 0.54 under a 1-mA current,which is much higher than ER under 1 mA for the patterned weak phase-separated La_（0.67）Ca_（0.33）MnO_3 and La_（0.85）Sr_（0.15）MnO_3 microbridges with 50-μm width.More interestingly,for the patterned LPCMO microbridge,the maximum of ER can reach 0.6 under a small current of 100 μ.A.The results were explained by considering the coexistence of ferromagnetic metallic phase with the charge-ordered phase,and the variation of the phase separation with electric current.
基金sponsored by the National Natural Science Foundation of China(No.52372113).
文摘Orientation anisotropy is a well-known essential character for polarization characteristics of ferroelectric materials,which has been widely investigated in conventional ferroelectric random access memories.In this work,we study the effects of orientation on the tunneling electroresistance(TER)of ferroelectric tunnel junctions(FTJs).Rhombohedral Pb(Zr_(0.7),Ti_(0.3))O_(3)(PZT)that has the polar axis along the(111)orientation is adopted as potential barriers and two kinds of FTJs that are composed of(001)-and(II1)-oriented PZT barriers and Nb:SrTiO_(3)(Nb:STO)electrodes,respectively,are fabricated.The(111)-oriented P1PZT/Nb:STO FTJ exhibits a giant ON/OFFratio of~1.9×10^(5),about 30 times that of the(001)-oriented device,due to the lowered PZT barrier in the ON state and the widen Schottky barrier in the OFF state based on current and capacitance analyses.In addition,compared to the(001)-oriented device,the(111)-oriented FTJ shows a sharper and faster switching between the ON and OFF states according to the nucleation-limited-switching dynamics model,giving rise to good linearity in memristive behaviors for synaptic plasticity and reliable retention and endurance properties for the resistance switching.The improved TER properties are ascribed to larger effective polarizations and 180°switching in the(111)-oriented PZT barrier.These results facilitate the design and fabrication of high-performance FTJ devices with the optimization of crystallographic orientation and polarization switching characteristics.
基金Project supported by the National Basic Research Program of China (Grant No. 2007CB925002)the National High Technology Research and Development Program of China (Grant No. 2008AA031401)and Chinese Academy of Sciences
文摘We report that fully transparent resistive random access memory （TRRAM） devices based on ITO/TiO2/ITO sandwich structure, which are prepared by the method of RF magnetron sputtering, exhibit excellent switching stability. In the visible region （400 800 nm in wavelength） the TRRAM device has a transmittance of more than 80%. The fabricated TRRAM device shows a bipolar resistance switching behaviour at low voltage, while the retention test and rewrite cycles of more than 300,000 indicate the enhancement of switching capability. The mechanism of resistance switching is further explained by the forming and rupture processes of the filament in the TiO2 layer with the help of more oxygen vacancies which are provided by the transparent ITO electrodes.
基金Project supported by the National Natural Science Foundation of China(Grant No.11674298)the National Key Research and Development Program of China(Grant No.2017YFA0403502)the Users with Excellence Project of Hefei Science Center CAS(Grant No.2018HSC-UE013).
文摘We report an investigation into the magnetoresistance(MR)of La_(0.8)Ba_(0.2)MnO_(3)ultrathin films with various thicknesses.While the 13 nm-thick film shows the commonly reported negative magnetoresistive effect,the 6 nm-and 4 nm-thick films display unconventional positive magnetoresistive(PMR)behavior under certain conditions.As well as the dependence on the film's thickness,it has been found that the electrical resistivity and the PMR effect of the thinner films are very dependent on the test current.For example,the magnetoresistive ratio of the 4 nm-thick film changes from+46%to-37%when the current is increased from 10 nA to 100 nA under 15 kOe at 40 K.In addition,the two thinner films present opposite changes in electrical resistivity with respect to the test current,i.e.,the electroresistive(ER)effect,at low temperatures.We discuss the complex magnetoresistive and ER behaviors by taking account of the weak contacts at grain boundaries between ferromagnetic metallic(FMM)grains.The PMR effect can be attributed to the breaking of the weak contacts due to the giant magnetostriction of the FMM grains under a magnetic field.Considering the competing effects of the conductive filament and local Joule self-heating at grain boundaries on the transport properties,the dissimilar ER effects in the two thinner films are also understandable.These experimental findings provide an additional approach for tuning the magnetoresistive effect in manganite films.
基金the National Natural Science Foundation of China (Grant No.10774040) and the joint Chinese-Russian Project for their financial supports
文摘Strontium doped perovskite-type Nd0.7Sr0.3MnO3 ceramics were synthesized completely by high-energy ball milling raw oxides of Nd2O3, SrCO3 and MnO2. The optimal ball milling time and mass ratio of milling balls to raw materials are 4 h and 10：1, respectively. The grain size of as-milled Nd0.7Sr0.3MnO3 ceramics ranges from 51 to 93 nm, and the fine particles contain two phases of crystalline phase and amorphous phase. For the Nd0.7r0.3MnO3 synthesized by ball milling and sequent heat treatment, a remarkable colossal electroresistance （CER） effect is observed and the CER ratio reaches 900% at Curie temperature Tc when the load voltage increases from 0.1 to 0.8 V.
基金Project supported by the National Natural Science Foundation of China (Grant Nos.11874244 and 11974222)。
文摘Modulation between optical and ferroelectric properties was realized in a lateral structured ferroelectric CuInP_(2)S_(6)(CIPS)/semiconductor MoS_(2) van der Waals heterojunction.The ferroelectric hysteresis loop area was modulated by the optical field.Two types of photodetection properties can be realized in a device by changing the ON and OFF states of the ferroelectric layer.The device was used as a photodetector in the OFF state but not in the ON state.The higher tunnelling electroresistance(~1.4×10^(4))in a lateral structured ferroelectric tunnelling junction was crucial,and it was analyzed and modulated by the barrier height and width of the ferroelectric CIPS/semiconductor MoS_(2) Schottky junction.The new parameter of the ferroelectric hysteresis loop area as a function of light intensity was introduced to analyze the relationship between the ferroelectric and photodetection properties.The proposed device has potential application as an optoelectronic sensory cell in the biological nervous system or as a new type of photodetector.
基金The work at PSU was supported in part by the DOE(Grant No.DE-FG02-08ER4653)the NSF(Grant No.DMR-1411166)The work at USTC was supported by NSFC and NBRPC(2016YFA0300103).
文摘Although the basic concept was proposed only about 10 years ago,multiferroic tunnel junctions(MFTJs)with a ferroelectric barrier sandwiched between two ferromagnetic electrodes have already drawn considerable interests,driven mainly by its potential applications in multi-level memories and electric field controlled spintronics.The purpose of this article is to review the recent progress of all-perovskite MFTJs.Starting from the key functional properties of the tunneling magnetoresistance,tunneling electroresistance,and tunneling electromagnetoresistance effects,we discuss the main origins of the tunneling electroresistance effect,recent progress in achieving multilevel resistance states in a single device,and the electrical control of spin polarization and transport through the ferroelectric polarization reversal of the tunneling barrier.
基金the National Natural Science Foundation of China(Grant No.10334070)the National Key Basic Research Program of China(Grant No.2004CB619004)
文摘We report here studies on the influence of oxygen pressure on the electroresis-tance behavior of La0.9Sr0.1MnO3 thin films fabricated by laser molecular beam epi-taxy.It was found that the film deposited at lower oxygen pressure shows larger c-axis parameter,higher resistance,and more distinct electroresistance.These results reveal that the electroresistance of manganite thin films can be tuned by the conditions of film fabrication.
