Perovskite-structured nickelates,ReNiO_(3)(Re=rare earth),have long garnered significant research interest due to their sharp and highly tunable metal-insulator transitions(MITs).Doping the parent compound ReNiO_(3)wi...Perovskite-structured nickelates,ReNiO_(3)(Re=rare earth),have long garnered significant research interest due to their sharp and highly tunable metal-insulator transitions(MITs).Doping the parent compound ReNiO_(3)with alkaline earth metal can substantially suppress this MIT.Recently,intriguing superconductivity has been discovered in doped infinite-layer nickelates(ReNiO_(2)),while the mechanism behind A-site doping-suppressed MIT in the parent compound ReNiO_(3)remains unclear.To address this problem,we grew a series of Nd_(1−x)Sr_(x)NiO_(3)(NSNO,x=0–0.2)thin films and conducted systematic electrical transport measurements.Our resistivity and Hall measurements suggest that Sr-induced excessive holes are not the primary reason for MIT suppression.Instead,first-principles calculations indicate that Sr cations,with larger ionic radius,suppress breathing mode distortions and promote charge transfer between oxygen and Ni cations.This process weakens Ni–O bond disproportionation and Ni^(2+)/Ni^(4+)charge disproportionation.Such significant modulations in lattice and electronic structures convert the ground state from a charge-disproportionated antiferromagnetic insulator to a paramagnetic metal,thereby suppressing the MIT.This scenario is further supported by the weakened MIT observed in the tensile-strained NSNO/SrTiO_(3)(001)films.Our work reveals the A-side doping-modulated electrical transport of perovskite nickelate films,providing deeper insights into novel electric phases in these strongly correlated nickelate systems.展开更多
As a prototypical half-metallic ferromagnet,La_(0.67)Sr_(0.33)MnO_(3)(LSMO)has been extensively studied due to its versatile physical properties and great potential in spintronic applications.However,the weak perpendi...As a prototypical half-metallic ferromagnet,La_(0.67)Sr_(0.33)MnO_(3)(LSMO)has been extensively studied due to its versatile physical properties and great potential in spintronic applications.However,the weak perpendicular magnetic anisotropy(PMA)limits the controllability and detection of magnetism in LSMO,thus hindering the realization of oxide-based spintronic devices with low energy consumption and high integration level.Motivated by this challenge,we develop an experimental approach to enhance the PMA of LSMO epitaxial films.By cooperatively introducing 4d Ru doping and a moderate compressive strain,the maximum uniaxial magnetic anisotropy in Ru-doped LSMO can reach 3.0×10^(5)J/m^(3)at 10 K.Furthermore,we find a significant anisotropic magnetoresistance effect in these Ru-doped LSMO films,which is dominated by the strong PMA.Our findings offer an effective pathway to harness and detect the orientations of magnetic moments in LSMO films,thus promoting the feasibility of oxide-based spintronic devices,such as spin valves and magnetic tunnel junctions.展开更多
The interfacial enhanced ferromagnetism in maganite/ruthenate system is regarded as a promising path to broaden the potential of oxide-based electronic device applications.Here,we systematically studied the physical p...The interfacial enhanced ferromagnetism in maganite/ruthenate system is regarded as a promising path to broaden the potential of oxide-based electronic device applications.Here,we systematically studied the physical properties of La_(1-x)Ca_(x)MnO_(3)/SrRuO_(3)superlattices and compared them with the La1-x Cax MnO_(3)thin films and bulk compounds.The La_(1-x)Ca_(x)MnO_(3)/SrRuO_(3)superlattices exhibit significant enhancement of Curie temperature(TC)beyond the corresponding thin films and bulks.Based on these results,we constructed an extended phase diagram of La_(1-x)Ca_(x)MnO_(3)under interfacial engineering.We considered the interfacial charge transfer and structural proximity effects as the origin of the interfaceinduced high TC.The structural characterizations revealed a pronounced increase of B-O-B bond angle,which could be the main driving force for the high TCin the superlattices.Our work inspires a deeper understanding of the collective effects of interfacial charge transfer and structural proximity on the physical properties of oxide heterostructures.展开更多
基金supported by the National Key Research and Development Program of China(Grant Nos.2023YFA1406404 and 2020YFA0309100)the National Natural Science Foundation of China(Grant Nos.12074365,12374094,12304153,U2032218,and 11974326),the National Natural Science Foundation of China(Grant No.12274120)+6 种基金CAS Project for Young Scientists in Basic Research(Grant No.YSBR-084)the Fundamental Research Funds for the Central Universities(Grant Nos.WK9990000102 and WK2030000035)Anhui Provincial Natural Science Foundation(Grant No.2308085MA15)Hefei Science Center CAS Foundation(Grant Nos.2021HSC-CIP017 and 2016HSC-IU06)the China Postdoctoral Science Foundation(Grant No.2022M713060)the starting funds from Northwest Universitysupport from the Vienna Scientific Cluster(VSC)for the first-principles calculations。
文摘Perovskite-structured nickelates,ReNiO_(3)(Re=rare earth),have long garnered significant research interest due to their sharp and highly tunable metal-insulator transitions(MITs).Doping the parent compound ReNiO_(3)with alkaline earth metal can substantially suppress this MIT.Recently,intriguing superconductivity has been discovered in doped infinite-layer nickelates(ReNiO_(2)),while the mechanism behind A-site doping-suppressed MIT in the parent compound ReNiO_(3)remains unclear.To address this problem,we grew a series of Nd_(1−x)Sr_(x)NiO_(3)(NSNO,x=0–0.2)thin films and conducted systematic electrical transport measurements.Our resistivity and Hall measurements suggest that Sr-induced excessive holes are not the primary reason for MIT suppression.Instead,first-principles calculations indicate that Sr cations,with larger ionic radius,suppress breathing mode distortions and promote charge transfer between oxygen and Ni cations.This process weakens Ni–O bond disproportionation and Ni^(2+)/Ni^(4+)charge disproportionation.Such significant modulations in lattice and electronic structures convert the ground state from a charge-disproportionated antiferromagnetic insulator to a paramagnetic metal,thereby suppressing the MIT.This scenario is further supported by the weakened MIT observed in the tensile-strained NSNO/SrTiO_(3)(001)films.Our work reveals the A-side doping-modulated electrical transport of perovskite nickelate films,providing deeper insights into novel electric phases in these strongly correlated nickelate systems.
基金supported by the National Basic Research Program of China(Grant No.2020YFA0309100)the National Natural Science Foundation of China(Grant Nos.12074365,U2032218,and 11974326)+1 种基金the Fundamental Research Funds for the Central Universities(Grant Nos.WK9990000102 and WK2030000035)the China Postdoctoral Science Foundation(Gaint No.2022M713060)。
文摘As a prototypical half-metallic ferromagnet,La_(0.67)Sr_(0.33)MnO_(3)(LSMO)has been extensively studied due to its versatile physical properties and great potential in spintronic applications.However,the weak perpendicular magnetic anisotropy(PMA)limits the controllability and detection of magnetism in LSMO,thus hindering the realization of oxide-based spintronic devices with low energy consumption and high integration level.Motivated by this challenge,we develop an experimental approach to enhance the PMA of LSMO epitaxial films.By cooperatively introducing 4d Ru doping and a moderate compressive strain,the maximum uniaxial magnetic anisotropy in Ru-doped LSMO can reach 3.0×10^(5)J/m^(3)at 10 K.Furthermore,we find a significant anisotropic magnetoresistance effect in these Ru-doped LSMO films,which is dominated by the strong PMA.Our findings offer an effective pathway to harness and detect the orientations of magnetic moments in LSMO films,thus promoting the feasibility of oxide-based spintronic devices,such as spin valves and magnetic tunnel junctions.
基金Project supported by the National Key Research and Development Program of China(Grant Nos.2016YFA0401003,2017YFA0403502,and2020YFA0309100)the National Natural Science Foundation of China(Grant Nos.11974326,12074365,11804342,U2032218,and 51872278)+1 种基金the Fundamental Research Funds for the Central Universities,China(Grant Nos.WK2030000035 and WK2340000102)Hefei Science Center of Chinese Academy of Sciences(Grant No.2020HSC-UE014)。
文摘The interfacial enhanced ferromagnetism in maganite/ruthenate system is regarded as a promising path to broaden the potential of oxide-based electronic device applications.Here,we systematically studied the physical properties of La_(1-x)Ca_(x)MnO_(3)/SrRuO_(3)superlattices and compared them with the La1-x Cax MnO_(3)thin films and bulk compounds.The La_(1-x)Ca_(x)MnO_(3)/SrRuO_(3)superlattices exhibit significant enhancement of Curie temperature(TC)beyond the corresponding thin films and bulks.Based on these results,we constructed an extended phase diagram of La_(1-x)Ca_(x)MnO_(3)under interfacial engineering.We considered the interfacial charge transfer and structural proximity effects as the origin of the interfaceinduced high TC.The structural characterizations revealed a pronounced increase of B-O-B bond angle,which could be the main driving force for the high TCin the superlattices.Our work inspires a deeper understanding of the collective effects of interfacial charge transfer and structural proximity on the physical properties of oxide heterostructures.
