Coexistence of ferromagnetism and ferroelasticity in a single material is an intriguing phenomenon,but has been rarely found.Here we studied both the ferromagnetism and ferroelasticity in a group of LaCoO3 films with ...Coexistence of ferromagnetism and ferroelasticity in a single material is an intriguing phenomenon,but has been rarely found.Here we studied both the ferromagnetism and ferroelasticity in a group of LaCoO3 films with systematically tuned atomic structures.We found that all films exhibit ferroelastic domains with four-fold symmetry and the larger domain size(higher elasticity)is always accompanied by stronger ferromagnetism.We performed synchrotron x-ray diffraction studies to investigate the backbone structure of the CoO6 octahedra,and found that both the ferromagnetism and the elasticity are simultaneously enhanced when the in-plane Co–O–Co bond angles are straightened.Therefore the study demonstrates the inextricable correlation between the ferromagnetism and ferroelasticity mediated through the octahedral backbone structure,which may open up new possibilities to develop multifunctional materials.展开更多
Ⅰ. INTRODUCTIONA number of investigators have reported recently that crystal grains of RBa<sub>2</sub>Cu<sub>3</sub>O<sub>7-x</sub> invariably contain at least one set of parallel...Ⅰ. INTRODUCTIONA number of investigators have reported recently that crystal grains of RBa<sub>2</sub>Cu<sub>3</sub>O<sub>7-x</sub> invariably contain at least one set of parallel（110）twin domain, where R represents La, Y, Eu and Tl. The grain with twin domain is confirmed to be a superconducting phase of orthorhombic structure. Twins of this kind are usually called transformation twins（in contrast to, for instance, growth twins or deformation twins and twin boundary）. However, de-展开更多
This paper presents an overview of the growth of Bi2Se3, a prototypical three-dimensional topological insulator, by molecular-beam epitaxy on various substrates. Comparison is made between the growth of Bi2 Se3 （111...This paper presents an overview of the growth of Bi2Se3, a prototypical three-dimensional topological insulator, by molecular-beam epitaxy on various substrates. Comparison is made between the growth of Bi2 Se3 （111） on van der Waals （vdW） and non-vdW substrates, with attention paid to twin suppression and strain. Growth along the [221] direction of Bi2Se3 on InP （001） and GaAs （001） substrates is also discussed.展开更多
It has been confirmed that YBa<sub>2</sub>Cu<sub>3</sub>O<sub>7-x</sub> superconducting phase is an orthorhombic one belonging to the space group Pmmm with lattice constants a=3. 89...It has been confirmed that YBa<sub>2</sub>Cu<sub>3</sub>O<sub>7-x</sub> superconducting phase is an orthorhombic one belonging to the space group Pmmm with lattice constants a=3. 893A, b=3.820A and c=11.688A. There are many twin domains in this superconducting material studied with a TEM in this work. The reason for the formation of this twin domain structure and the characteristics of phase transformation have also been discussed.展开更多
Our scanning tunneling microscopy (STM) study observes, for the first time, twin domain boundary (TDB) formations on the surface of WTe2 single crystal, which is glued by solidifying indium to Si substrate. In these T...Our scanning tunneling microscopy (STM) study observes, for the first time, twin domain boundary (TDB) formations on the surface of WTe2 single crystal, which is glued by solidifying indium to Si substrate. In these TDB regions, a large inhomogeneous strain field, especially a critical shear strain of about 7%, is observed by geometric phase analysis. This observation does not obey the old believe that a small mechanical stress is sufficient to drive thermally-induced TDB formations in two-dimensional materials. To resolve the contradiction, we perform density functional theory calculations combined with elasticity theory analysis, which show that TDBs on WTe2 are entirely displacement-induced, for which a critical strain is necessary to overcome the onset barrier.展开更多
YBa2Cu3O7-x （YBCO） superconducting film was fabricated on {001} LaAlO3 （LAO） substrate by pulse laser deposition （PLD）, and its microstructure was examined by high resolution X-ray diffraction technology （HRXRD...YBa2Cu3O7-x （YBCO） superconducting film was fabricated on {001} LaAlO3 （LAO） substrate by pulse laser deposition （PLD）, and its microstructure was examined by high resolution X-ray diffraction technology （HRXRD）, such as pole figure, rocking curve, reciprocal space mapping. The results show that the YBCO crystalline alignment is almost {001}YBCO//{001}LAO, 100YBCO//100LAO besides 2% {001}YBCO//{001}LAO, 110YBCO//100LAO. The out-plane alignment of YBCO is some spreading （the breadth is 0.75°）. There are 90°±0.65°110 twin domains in the film, which is caused by the high local stress and stress difference between 100 and 010 during the tetragonal to orthorhombic phase transition.展开更多
基金the National Natural Science Foun-dation of China(Grant Nos.52072244 and 12104305)the Science and Technology Commission of Shanghai Municipal-ity(Grant No.21JC1405000)the ShanghaiTech Startup Fund.This research used resources of the Advanced Photon Source,a U.S.Department of Energy(DOE)Office of Sci-ence User Facility operated for the DOE Office of Science by Argonne National Laboratory under Contract No.DE-AC02-06CH11357.
文摘Coexistence of ferromagnetism and ferroelasticity in a single material is an intriguing phenomenon,but has been rarely found.Here we studied both the ferromagnetism and ferroelasticity in a group of LaCoO3 films with systematically tuned atomic structures.We found that all films exhibit ferroelastic domains with four-fold symmetry and the larger domain size(higher elasticity)is always accompanied by stronger ferromagnetism.We performed synchrotron x-ray diffraction studies to investigate the backbone structure of the CoO6 octahedra,and found that both the ferromagnetism and the elasticity are simultaneously enhanced when the in-plane Co–O–Co bond angles are straightened.Therefore the study demonstrates the inextricable correlation between the ferromagnetism and ferroelasticity mediated through the octahedral backbone structure,which may open up new possibilities to develop multifunctional materials.
基金Project supported by the Open Research Laboratory of High Performance CeramicsSuperfine Microstructural Studies
文摘Ⅰ. INTRODUCTIONA number of investigators have reported recently that crystal grains of RBa<sub>2</sub>Cu<sub>3</sub>O<sub>7-x</sub> invariably contain at least one set of parallel（110）twin domain, where R represents La, Y, Eu and Tl. The grain with twin domain is confirmed to be a superconducting phase of orthorhombic structure. Twins of this kind are usually called transformation twins（in contrast to, for instance, growth twins or deformation twins and twin boundary）. However, de-
基金supported by the Research Grant Council (RGC) of Hong Kong Special Administrative Region for its financial support under the General Research Funds (Grant Nos. 706110 and 706111)the SRFDP and RGCERG Joint Research Scheme sponsored by the RGC of Hong Kong and the Ministry of Education of China (M-HKU709/l2)
文摘This paper presents an overview of the growth of Bi2Se3, a prototypical three-dimensional topological insulator, by molecular-beam epitaxy on various substrates. Comparison is made between the growth of Bi2 Se3 （111） on van der Waals （vdW） and non-vdW substrates, with attention paid to twin suppression and strain. Growth along the [221] direction of Bi2Se3 on InP （001） and GaAs （001） substrates is also discussed.
文摘It has been confirmed that YBa<sub>2</sub>Cu<sub>3</sub>O<sub>7-x</sub> superconducting phase is an orthorhombic one belonging to the space group Pmmm with lattice constants a=3. 893A, b=3.820A and c=11.688A. There are many twin domains in this superconducting material studied with a TEM in this work. The reason for the formation of this twin domain structure and the characteristics of phase transformation have also been discussed.
基金We thank the Ministry of Science and Technology of China (Nos. 2016YFA0301003 and 2016YFA0300403)the National Natural Science Foundation of China (Nos. 11521404, 11634009, U1632102, 11504230, 11674222, 11574202, 11674226, 11574201, 11655002, and U1632272) for partial support+4 种基金W Y. X. was supported by the National Science Foundation Award (No. DMR-1305293)S. B.乙 was supported by the US Department of Energy (DOE)(No. DESC0002623)The supercomputer time sponsored by National Energy aesearch Scientific Computing Center (NERSC) under DOE contract (No. DE-AC02-05CH11231)the Center for Computational Innovations (CCI) at Rensselaer Polytechnic Institute (RPI) are also acknowledgedThis project has been supported by a grant &om Science and Technology Commission of Shanghai Municipality (No. 16DZ2260200) and the Strategic Priority Research Program of Chinese Academy of Sciences (No. XDB28000000).
文摘Our scanning tunneling microscopy (STM) study observes, for the first time, twin domain boundary (TDB) formations on the surface of WTe2 single crystal, which is glued by solidifying indium to Si substrate. In these TDB regions, a large inhomogeneous strain field, especially a critical shear strain of about 7%, is observed by geometric phase analysis. This observation does not obey the old believe that a small mechanical stress is sufficient to drive thermally-induced TDB formations in two-dimensional materials. To resolve the contradiction, we perform density functional theory calculations combined with elasticity theory analysis, which show that TDBs on WTe2 are entirely displacement-induced, for which a critical strain is necessary to overcome the onset barrier.
基金Project (50972019) supported by the National Natural Science Foundation of ChinaProject (2011CBA00105) supported by the National Basic Research Program of China
文摘YBa2Cu3O7-x （YBCO） superconducting film was fabricated on {001} LaAlO3 （LAO） substrate by pulse laser deposition （PLD）, and its microstructure was examined by high resolution X-ray diffraction technology （HRXRD）, such as pole figure, rocking curve, reciprocal space mapping. The results show that the YBCO crystalline alignment is almost {001}YBCO//{001}LAO, 100YBCO//100LAO besides 2% {001}YBCO//{001}LAO, 110YBCO//100LAO. The out-plane alignment of YBCO is some spreading （the breadth is 0.75°）. There are 90°±0.65°110 twin domains in the film, which is caused by the high local stress and stress difference between 100 and 010 during the tetragonal to orthorhombic phase transition.
