arXiv subjects

Yubin Hou

Publications and source records attributed to Yubin Hou.

10 recordsLinked to original sources

arXiv2026

Magnetic anisotropic pinning and symmetric breaking induced by interfacial coupling in topological-like ruthenate superlattices

Interfacial engineering enables various emergent effects such as spin reorientations and transport anisotropy. Noncollinear spin textures are essential for realizing many emergent quantum transport phenomena. However, driving such spin structures requires precise control of the interfacial magnetic coupling in complex oxide heterostructures. Here, by utilizing competing exchange interactions at the interface between ferromagnetic metal SrRuO3 and ferromagnetic insulator LaCoO3, we discovered a noncollinear spin configuration in SrRuO3 sublayers. Magnetic stripes were induced by out-of-plane rather than in-plane magnetic fields, indicating strong anisotropy pinning in our superlattices. The observed magneto-transport anisotropy is well explained by our proposed spin configurations, accounting for contributions from both bulk and interface of the SrRuO3 layers. More interestingly, magnetic skymionic textures were absent even at high magnetic fields. The interfacial exchange interaction overwhelms the Dzyaloshinskii-Moriya interaction (DMI) that stabilizes skyrmions, featuring a higher exchange coupling energy than that for the topological spin textures. Our work highlights the potential of interfacial engineering in tuning the spintronic properties by designing proper interfacial interactions.

cond-mat.str-el↗

arXiv2025

Giant plateau-like topological Hall effect controlled by tailoring the magnetic exchange stiffness in a kagome magnet

The ferrimagnet TbMn6Sn6 has attracted vast attention, because its pristine Mn kagome lattice with strong spin-orbit coupling and out-of-plane Tb-Mn exchange supports quantum-limit Chern topological magnetism which can be described by the simple spinless Haldane model. We unveil herein that engineering the kagome lattice through partial substitution of Mn with nonmagnetic Cr induces a striking structural reorganization-Cr preferentially concentrates within a single Mn layer per unit cell, reducing the crystal symmetry from the D6h point group to the C2. This tailored structure configuration gives rise to a plateau-like topological Hall effect (THE), achieving a record-breaking resistivity of 19.1 ohm cm among bulk systems. Complementary magnetic force microscopy measurements unveil a magnetic domain transition near 1 T at 180 K, aligning with the field-dependent phase diagram of the THE. Our direct visualization of the magnetic domain structure underscores the critical role of broken kagome lattice symmetry in generating distinct exchange stiffness between the two Mn layers. These findings establish a new paradigm for exploring exotic states in kagome topological magnets and provide a proof-of-principle strategy for unraveling the interplay between magnetism and emergent topological properties in kagome systems.

cond-mat.str-el↗

arXiv2025

Anomalous magnetoresistance in an antiferromagnetic Kagome semimetal heterostructures

Antiferromagnetic Kagome semimetals have attracted tremendous attentions for their potential application in antiferromagnetic topological spintronics. Effectively manipulating Kagome antiferromagnetic states could reveal abundant physical phenomena induced from quantum interactions between topology, spin, and correlation. Here, we achieved tunable spin textures of FeSn thin films via introducing interfacial Dzyaloshinskii Moriya interaction from heavy-metal Pt overlayer. With increasing FeSn thickness, the variable spin textures result in gradual change in Hall resistivity and magnetoresistance. Importantly, an unconventional damped oscillatory-like behavior of magnetoresistance at relatively low magnetic field can be observed in thin FeSn-Pt samples. This oscillatory like magnetoresistance feature was confirmed to be related to the special topological spin textures revealed by magnetic force microscopy measurements. The formation of rich variety of topological spin textures in association with exotic magneto-transport properties in antiferromagnetic Kagome FeSn heterostructures offers new perspectives for understanding the novel emergent phenomena in Kagome antiferromagnets.

cond-mat.mtrl-sci↗

arXiv2025

Giant Self Spin-Valve Effect in the Kagome Helimagnet

Kagome magnets can combine non-trivial band topology and electron correlations, offering a versatile playground for various quantum phenomena. In this work we propose that kagome magnets with frustrated interlayer interactions can intrinsically support a self spin-valve effect, and experimentally confirm this in the kagome helimagnet TmMn$_6$Sn$_6$. Under a magnetic field perpendicular to the helical axis, using magnetic force microscopy we observed stripe domains that stack strictly along the helical axis, which we attribute to the stability loss of the kagome helimagnetic state. Such a domain pattern spontaneously mimics the artificial multilayered structure in traditional spin valves, which, combined with the high spin polarization, leads to a giant magnetoresistance (GMR) ratio over 160%. This discovery opens an avenue to realize inherent spin valves in a variety of quantum magnets, and can hold promise in future spintronics.

cond-mat.str-el↗

arXiv2021

Quantum percolation and magnetic nano-dropletstates in electronically phase-separated manganite nanowires

One-dimensional (1D) confinement has been revealed to effectively tune the properties of materials in homogeneous states. The 1D physics can be further enriched by electronic inhomogeneity, which unfortunately remains largely unknown. Here we demonstrate the ultra-high sensitivity to magnetic fluctuations and the tunability of phase stability in the electronic transport properties of self-assembled electronically phase-separated manganite nanowires with extreme aspect ratio. The onset of magnetic nano-droplet state, a precursor to the ferromagnetic metallic state, is unambiguously revealed, which is attributed to the small lateral size of the nanowires that is comparable to the droplet size. Moreover, the quasi-1D anisotropy stabilizes thin insulating domains to form intrinsic tunneling junctions in the low temperature range, which is robust even under magnetic field up to 14 T, and thus essentially modifies the classic 1D percolation picture to stabilize a novel quantum percolation state. A new phase diagram is therefore established for the manganite system under quasi-1D confinement for the first time. Our findings offer new insight to understand and manipulate the colorful properties of the electronically phase-separated systems via dimensionality engineering.

cond-mat.str-el↗

arXiv2018

Atomically resolved probe-type scanning tunneling microscope for use in harsh vibrational cryogen-free superconducting magnet

We present a probe-type scanning tunneling microscope (STM) with atomic resolution that is designed to be directly inserted and work in a harsh vibrational cryogen-free superconducting magnet system. When a commercial variable temperature insert (VTI) is installed in the magnet and the STM is in turn housed in the VTI, a lowest temperature of 1.6 K can be achieved, where the STM still operates well. We have tested it in an 8 T superconducting magnet cooled with the pulse-tube cryocooler (PTC) and obtained atomically revolved graphite and NiSe2 images as well as the scanning tunneling spectrum (STS, i.e. dI/dV spectrum) data of the latter near its critical temperature, which show the formation process of the superconducting gap as a function of temperature. The drifting rates of the STM at 1.6 K in X-Y plane and Z direction are 1.15 and 1.71 pm/min respectively. Noise analysis for the tunneling current shows that the amplitudes of the dominant peaks (6.84 and 10.25Hz) are low. This is important as a cryogen-free magnet system has long been considered too harsh for any atomic resolution measurement.

physics.ins-det↗

arXiv2018

Multiple structure and symmetry types in narrow temperature and magnetic field ranges in two-dimensional Cr2Ge2Te6 crystal

Multiple structure and symmetry types and their transformations are discovered in quasi-two-dimensional (quasi-2D) Cr2Ge2Te6 crystal in surprisingly very narrow temperature range of 2 K and magnetic field range of 0.07 T using a homebuilt magnetic force microscope (MFM). A series of basic domain patterns are extracted from the MFM images. Some of them seem unique to 2-D materials as they are not observed in 3-D materials, such as self-fitting disks, and fine ladder structure within Y-connected walls. Based on these findings, a phase map is drawn for the magnetic phase structures. The symmetry of the patterns are discussed. The results are not only important in developing new theories but also highly desirable in applications.

cond-mat.mtrl-sci↗

arXiv2016

Evolution and control of the phase competition morphology in a manganite film

The competition among different phases in perovskite manganites is pronounced since their energies are very close under the interplay of charge, spin, orbital and lattice degrees of freedom. To reveal the roles of underlying interactions, many efforts have been devoted towards directly imaging phase transitions at microscopic scales. Here we show images of the charge-ordered insulator (COI) phase transition from a pure ferromagnetic metal with reducing field or increasing temperature in a strained phase-separated manganite film, using a home-built magnetic force microscope. Compared with the COI melting transition, this reverse transition is sharp, cooperative and martensitic-like with astonishingly unique yet diverse morphologies. The COI domains show variable-dimensional growth at different temperatures and their distribution can illustrate the delicate balance of the underlying interactions in manganites. Our findings also display how phase domain engineering is possible and how the phase competition can be tuned in a controllable manner.

cond-mat.str-el↗

arXiv2015

Quality Atomic Resolution Scanning Tunneling Microscope Imaging up to 27 T in Water-cooled Magnet

We report the achievement of the first atomically resolved scanning tunneling microscope (STM) imaging in a water-cooled magnet (WM), where the extremely harsh vibrations and noises have been the major challenge. This homebuilt WM-STM features an ultra-rigid and compact scan head in which the coarse approach is driven by our new design of the TunaDrive piezoelectric motor. A three-level spring hanging system is exploited for vibration isolation. Room-temperature raw-data images of graphite with quality atomic resolution were obtained in very high magnetic fields up to 27 T in a 32 mm bore WM whose absolute maximum field is 27.5 T at the power rating of 10 MW. This record of 27 T has exceeded the maximum field strength of the conventional superconducting magnets. Besides, our WM-STM has also paved the way to the STM imaging in the 45 T, 32 mm bore hybrid magnet, which is the world's flagship magnet and can produces the highest steady magnetic field at present.

cond-mat.mes-hall↗

arXiv2012

Report on the piezoelectric frequency effect in quartz and its possibility in other piezoelectric materials

We report the eigen-frequency shift induced by an applied voltage on quartz material. The samples are in the form of commercial 32 KHz quartz tuning forks used in watches. Three vibration modes are studied: one prong oscillates, two prongs oscillate in the same and opposite directions. They all show a parabolic dependence of the eigen-frequency shift on the bias voltage applied across the fork, which is explained owing to the voltage-induced internal stress that varies as the fork oscillates. Thus, this piezoelectric frequency effect is possible to exist in all piezoelectric materials. The average coefficient of the piezoelectric frequency effect is as low as several hundred nano-Hz per millivolt, implying that the most precise (nano-Hz) yet fast-response voltage-controlled oscillators and phase-locked loops can be built.

physics.ins-det↗