Geometric-Phase-Effect Tunnel-Splitting Oscillations in Single-Molecule Magnets with Fourth-Order Anisotropy Induced by Orthorhombic Distortion

利用低温光辅助扫描隧道显微镜对石英上本征生长的CsPbBr3铁电体单晶进行原子尺度表面成像

Atomic-Scale Surface Imaging of bulk Epitaxial CsPbBr3 Perovskite Single Crystals on Mica using Light Assisted Scanning Tunneling Microscopy at Low-Temperature (80 K)

利用低温光辅助STM在石英上研究CsPbBr3单晶表面重构，揭示其原子结构与能量稳定性。

LuFeO₃纳米颗粒中温度诱导的六方—正交相变

Temperature-Induced Hexagonal-Orthorhombic Phase Transition in Lutetium Ferrite Nanoparticles

本文结合多种表征与Gibbs模型，研究LuFeO₃纳米颗粒随烧结温度发生的六方—正交相变，并阐明相组成、晶格动力学与多铁性质的关联。

Oxide layer boron leads to reduced symmetry spin filtering magnetic tunnel junctions

Experimental studies of FeCoB/MgO/FeCoB tunnel junctions indicate that boron diffuses into MgO during rf-sputtering and forms polycrystalline Mg-B-O regions. These tunnel junctions provide high tunneling magnetoresistance values and low RA products. However the crystal structure of the Mg-B-O region remains unknown. Using density functional techniques, I examine three potential Mg(B) oxides including Mg$_{2}$B$_{2}$O$_{5}$ (monoclinic and triclinic) and the orthorhombic mineral Kotoite (Mg$_3$B$_2$O$_6$). Kotoite is the best candidate for formation in magnetic tunnel junctions. The (100) surfa…

正交晶系RhSi拓扑半金属晶体薄膜中的自旋-电荷转换

Spin-to-charge conversion in orthorhombic RhSi topological semimetal crystalline thin films

本研究通过逆自旋霍尔效应测量，在正交RhSi薄膜中实现了高效自旋-电荷转换，最大自旋霍尔电导率为126，界面自旋透明度达88%，为拓扑自旋电子学应用提供了新平台。

Scaling Behaviour of Low-Temperature Orthorhombic Domains in Prototypical High-Temperature Superconductor La$_{1.875}$Ba$_{0.125}$CuO$_{4}$

Translational/rotational symmetry breaking and recovery in condensed matter systems are closely related to exotic physical properties such as superconductivity (SC), magnetism, spin density waves (SDW) and charge density waves (CDW). The interplay between different order parameters is intricate and often subject to intense debate, as in the case of CDW order and superconductivity. In La1:875Ba0:125CuO4 (LBCO), the locations of CDW domains are found to be pinned on the nanometer size scale. Coherent X-ray diffraction techniques open routes to directly visualize the domain structures associated …

Tunneling magneto thermocurrent in CoFeB/MgO/CoFeB based magnetic tunnel junctions

We study the tunneling magneto thermopower and tunneling magneto thermocurrent of CoFeB/MgO/CoFeB magnetic tunnel junctions (MTJ). The devices show a clear change of the thermoelectric properties upon reversal of the magnetisation of the CoFeB layers from parallel to the antiparallel orientation. When switching from parallel to antiparallel the thermopower increases by up to 55% where as the thermocurrent drops by 45%. These observations can be well explained by the Onsager relations taking into account the tunneling magneto resistance of the MTJ. These findings contrast previous studies on Al…

Anisotropic tunneling magnetoresistance and tunneling anisotropic magnetoresistance: spin-orbit coupling in magnetic tunnel junctions

The effects of the spin-orbit interaction on the tunneling magnetoresistance of ferromagnet/semiconductor/normal metal tunnel junctions are investigated. Analytical expressions for the tunneling anisotropic magnetoresistance (TAMR) are derived within an approximation in which the dependence of the magnetoresistance on the magnetization orientation in the ferromagnet originates from the interference between Bychkov-Rashba and Dresselhaus spin-orbit couplings that appear at junction interfaces and in the tunneling region. We also investigate the transport properties of ferromagnet/semiconductor/…

Tunable magnetization in nanoscale LuFeO3: Role of morphology, ortho-hexa phase ratio and local structure

We have observed enhancement and shift in the spin reorientation transition temperature as a consequence of coexistence of orthorhombic and hexagonal phases and higher aspect ratio in nanoscale LuFeO3. Nanoparticles and nanofibers of LuFeO3 are considered for this work. Nanoparticles have 75 % orthorhombic phase and 25 % hexagonal phase, while nanofibers have 23% orthorhombic phase and 77%-hexagonal phase. Larger aspect ratio in case of nanofibers is seen to help strain-stabilize the hexagonal phase in the material. Magnetic measurements show significant difference in the magnetic behavior and…

Spin torque, tunnel-current spin polarization and magnetoresistance in MgO magnetic tunnel junctions

We examine the spin torque (ST) response of magnetic tunnel junctions (MTJs) with ultra-thin MgO tunnel barrier layers to investigate the relationship between the spin-transfer torque and the tunnel magnetoresistance (TMR) under finite bias. We find that the spin torque per unit current exerted on the free layer decreases by less than 10% over a bias range where the TMR decreases by over 40%. We examine the implications of this result for various spin-polarized tunneling models and find that it is consistent with magnetic-state-dependent effective tunnel decay lengths.

正交相MAPbI₃钙钛矿单晶中激子与带电载流子的光取向

Optical orientation of excitons and charged carriers in MAPbI$_3$ perovskite single crystals in the orthorhombic phase

本文在1.6 K下研究正交相MAPbI3钙钛矿单晶中激子与载流子的光取向，测得激子取向度达85%、电子和空穴g因子分别为2.83和0.54，并证明Dyakonov-Perel自旋弛豫机制在该体系中不活跃。

Tunneling Anisotropic Magnetoresistance of Helimagnet Tunnel Junctions

We theoretically investigate the angular and spin dependent transport in normal-metal/helical-multiferroic/ferromagnetic heterojunctions. We find a tunneling anisotropic magnetoresistance (TAMR) effect due to the spiral magnetic order in the tunnel junction and to an effective spin-orbit coupling induced by the topology of the localized magnetic moments in the multiferroic spacer. The predicted TAMR effect is efficiently controllable by an external electric field due to the magnetoelectric coupling.

Pinhole and tunneling conduction channels superimposed in magnetic tunnel junction: results and inferences

The influence of ballistic channels superimposed on tunneling conduction channels in magnetic tunnel junctions has been studied in a manganese oxide based tunneling device. Inversion of magnetoresistance has been observed in magnetic tunnel junctions with pinhole nanocontacts over a broad temperature range. The tunnel magnetoresistance undergoes a change of sign at higher bias and temperature. This phenomenon is attributed to the parallel conduction channels consisting of spin conserved ballistic transport through the pinhole contact where the transmission probability is close to unity and spi…