We reported a study of tunnel magnetoresistance(TMR)effect in single manganite nanowire via the combination of magnetotransport and magnetic force microscopy imaging.TMR value up to 290%has been observed in single(La1...We reported a study of tunnel magnetoresistance(TMR)effect in single manganite nanowire via the combination of magnetotransport and magnetic force microscopy imaging.TMR value up to 290%has been observed in single(La1-yPry)1-x CaxMnO3 nanowires with varying width.We find that the TMR effect can be explained in the scenario of opening and blockade of conducting channels from inherent magnetic domain evolutions.Our findings provide a new route to fabricate TMR junctions and point towards future improvements in complex oxide-based TMR spintronics.展开更多
Complex oxides have rich functionalities and advantages for future technologies.In many systems,quenched disorder often holds the key to determine their physical properties,and these properties can be further tuned by...Complex oxides have rich functionalities and advantages for future technologies.In many systems,quenched disorder often holds the key to determine their physical properties,and these properties can be further tuned by chemical doping.However,understanding the role of quenched disorder is complicated because chemical doping simultaneously alters other physical variables such as local lattice distortions and electronic and magnetic environments.Here,we show that spatial confinement is an effective approach to tuning the level of quenched disorder in a complex-oxide system while leaving other physical variables largely undisturbed.Through the confinement of a manganite system down to quasi-one-dimensional nanowires,we observed that the nature of its metal-insulator phase transition exhibits a crossover from a discontinuous to a continuous characteristic,in close accordance with quenched disorder theories.We argue that the quenched disorder,finite size,and surface effects all contribute to our experimental observations.Noticeably,with reduced nanowire width,the magnetoresistance shows substantial enhancement at low temperatures.Our findings offer new insight into experimentally tuning the quenched disorder effect to achieve novel functionalities at reduced dimensions.展开更多
Here,we present integrated nanorod arrays on microfluidic chips for fast and sensitive flow-through immunoassays of physiologically relevant macromolecules.Dense arrays of Au nanorods are easily fabricated through one...Here,we present integrated nanorod arrays on microfluidic chips for fast and sensitive flow-through immunoassays of physiologically relevant macromolecules.Dense arrays of Au nanorods are easily fabricated through one-step oblique angle deposition,which eliminates the requirement of advanced lithography methods.We report the utility of this plasmonic structure to improve the detection limit of the cardiac troponin I(cTnI)assay by over 6x 105-fold,reaching down to 33.9fg mL^(-1)(-1.4fM) compared with an identical assay on glass substrates.Through monolithic integration with microfluidic elements,the device enables a flow-through assay for quantitative detection of cTnI in the serum with a detection sensitivity of 6.9 pg mL^(-1)(-0.3 pM)in<6 min,which was 4000 times lower than conventional glass devices.This ultrasensitive detection arises from the large surface area for antibody conjugation and metal-enhanced fluorescent signals through plasmonic nanostructures.Moreover,due to the parallel arrangement of flow paths,simultaneous detection of multiple cancer biomarkers,including prostate-specific antigen and carcinoembryonic antigen,has been fulfilled with increased signal-to-background ratios.Given the high performance of this assay,together with its simple fabrication process that is compatible with standard mass manufacturing techniques,we expect that the prepared integrated nanorod device can bring on-site point-of-care diagnosis closer to reality.展开更多
基金Project supported by the National Key Research and Development Program of China(Grant No.2016YFA0300702)Shanghai Municipal Natural Science Foundation,China(Grant Nos.19ZR1402800,18JC1411400,18ZR1403200,and 17ZR1442600)+1 种基金the Program of Shanghai Academic Research Leader,China(Grant Nos.18XD1400600 and 17XD1400400)the China Postdoctoral Science Foundation(Grant Nos.2016M601488 and 2017T100265)
文摘We reported a study of tunnel magnetoresistance(TMR)effect in single manganite nanowire via the combination of magnetotransport and magnetic force microscopy imaging.TMR value up to 290%has been observed in single(La1-yPry)1-x CaxMnO3 nanowires with varying width.We find that the TMR effect can be explained in the scenario of opening and blockade of conducting channels from inherent magnetic domain evolutions.Our findings provide a new route to fabricate TMR junctions and point towards future improvements in complex oxide-based TMR spintronics.
基金the National Key Research and Development Program of China(Grant No.2016YFA0300702)the Shanghai Municipal Natural Science Foundation(Grant Nos.19ZR1402800,18JC1411400,18ZR1403200,and 17ZR1442600)+1 种基金the Program of Shanghai Academic Research Leader(Grant Nos.18XD1400600,and 17XD1400400)the China Postdoctoral Science Foundation(Grant Nos.2016M601488,and 2017T100265)。
文摘Complex oxides have rich functionalities and advantages for future technologies.In many systems,quenched disorder often holds the key to determine their physical properties,and these properties can be further tuned by chemical doping.However,understanding the role of quenched disorder is complicated because chemical doping simultaneously alters other physical variables such as local lattice distortions and electronic and magnetic environments.Here,we show that spatial confinement is an effective approach to tuning the level of quenched disorder in a complex-oxide system while leaving other physical variables largely undisturbed.Through the confinement of a manganite system down to quasi-one-dimensional nanowires,we observed that the nature of its metal-insulator phase transition exhibits a crossover from a discontinuous to a continuous characteristic,in close accordance with quenched disorder theories.We argue that the quenched disorder,finite size,and surface effects all contribute to our experimental observations.Noticeably,with reduced nanowire width,the magnetoresistance shows substantial enhancement at low temperatures.Our findings offer new insight into experimentally tuning the quenched disorder effect to achieve novel functionalities at reduced dimensions.
基金supported by the National Natural Science Foundation of China(Grant No.61701438)Shanghai Science and Technology Commission’s Scientific and Technological Innovation Action Plan(No.19495810300)+2 种基金Fundamental Research Funds for the Central Universities,China(Grant No.2020XZZX002-13)Zhejiang Province Key R&D programs(Nos.2020C03039,2020C01120,2021C03062,and 2021C03108)Science and Technology Service Network Initiative(STS)of the Chinese Academy of Sciences(No.KFJ-STS-QYZX-061).
文摘Here,we present integrated nanorod arrays on microfluidic chips for fast and sensitive flow-through immunoassays of physiologically relevant macromolecules.Dense arrays of Au nanorods are easily fabricated through one-step oblique angle deposition,which eliminates the requirement of advanced lithography methods.We report the utility of this plasmonic structure to improve the detection limit of the cardiac troponin I(cTnI)assay by over 6x 105-fold,reaching down to 33.9fg mL^(-1)(-1.4fM) compared with an identical assay on glass substrates.Through monolithic integration with microfluidic elements,the device enables a flow-through assay for quantitative detection of cTnI in the serum with a detection sensitivity of 6.9 pg mL^(-1)(-0.3 pM)in<6 min,which was 4000 times lower than conventional glass devices.This ultrasensitive detection arises from the large surface area for antibody conjugation and metal-enhanced fluorescent signals through plasmonic nanostructures.Moreover,due to the parallel arrangement of flow paths,simultaneous detection of multiple cancer biomarkers,including prostate-specific antigen and carcinoembryonic antigen,has been fulfilled with increased signal-to-background ratios.Given the high performance of this assay,together with its simple fabrication process that is compatible with standard mass manufacturing techniques,we expect that the prepared integrated nanorod device can bring on-site point-of-care diagnosis closer to reality.
