arXiv subjects

H. F. Ding

Publications and source records attributed to H. F. Ding.

5 recordsLinked to original sources

arXiv2023

Experimental verification of the inverse Anomalous spin Hall effect with perpendicular magnetic anisotropy Materials

In this work, the spin pumping technique was employed to investigate the anomalous inverse spin Hall effect in BIG/NiO/Fe samples where BIG[(Bi,Tm)3(Fe,Ga)5O12] exhibits perpendicular magnetic anisotropy. Our results reveal an intriguing phenomenon: when the magnetizations of both ferromagnetic layers align perpendicularly, a distinct spin-to-charge current conversion mechanism occurs. This conversion is intricately linked to the magnetization of the converting layer, spin polarization, and the spin current orientation.

cond-mat.mes-hall↗

arXiv2018

Anatomy of electrical signals and dc-voltage lineshape in spin torque ferromagnetic resonance

The electrical detection of spin torque ferromagnetic resonance (st-FMR) is becoming a popular method for measuring the spin-Hall angle of heavy metals (HM). However, various sensible analysis on the same material with either the same or different experimental setups yielded different spin-Hall angles with large discrepancy, indicating some missing ingredients in our current understanding of st-FMR. Here we carry out a careful analysis of electrical signals of the st-FMR in a HM/ferromagnet (HM/FM) bilayer with an arbitrary magnetic anisotropy. The FM magnetization is driven by two radio-frequency (rf) forces: the rf Oersted field generated by an applied rf electric current and the so called rf spin-orbit torque from the spin current flowing perpendicularly from the HM to the FM due to the spin-Hall effect. By using the universal form of the dynamic susceptibility matrix of magnetic materials at the st-FMR, the electrical signals originated from the anisotropic magnetoresistance, anomalous Hall effect and inverse spin-Hall effect are analysed and dc-voltage lineshape near the st-FMR are obtained. Angle-dependence of dc-voltage is given for two setups. A way of experimentally extracting the spin-Hall angle of a HM is proposed.

cond-mat.mes-hall↗

arXiv2017

Antiferromagnetic order in epitaxial FeSe films on SrTiO3

Single monolayer FeSe film grown on Nb-doped SrTiO$_3$(001) substrate shows the highest superconducting transition temperature (T$_C$ $\sim$ 100 K) among the iron-based superconductors (iron-pnictide), while T$_C$ of bulk FeSe is only $\sim$ 8 K. Antiferromagnetic spin fluctuations were believed to be crucial in iron-pnictides, which has inspired several proposals to understand the FeSe/SrTiO$_3$ system. Although bulk FeSe does not show the antiferromagnetic order, calculations suggest that the parent FeSe/SrTiO$_3$ films are AFM. Experimentally, due to lacking of direct probe, the magnetic state of FeSe/SrTiO$_3$ films remains mysterious. Here, we report the direct evidences of the antiferromagnetic order in the parent FeSe/SrTiO$_3$ films by the magnetic exchange bias effect measurements. The phase transition temperature is $\geq$ 140 K for single monolayer film. The AFM order disappears after electron doping.

cond-mat.supr-con↗

arXiv2012

Electronically Guided Self Assembly within Quantum Corrals

A grand challenge of nanoscience is to master the control of structure and properties in order to go beyond present day functionality. The creation of nanostructures via atom manipulation by means of a scanning probe represents one of the great achievements of the nano era. Here we build on this achievement to self-assemble nanostructures within quantum corrals. The structuring is guided by the quantum confinement of the electronic density of a silver metallic substrate within the corrals. We experimentally demonstrate different self-organized Gd atomic structures confined within 30-nm circular and triangular Fe quantum corrals. This approach enables the creation of model systems to explore and understand new nanomaterials and device prototypes.

cond-mat.mes-hall↗

arXiv2012

Spin Hall Angle Quantification from Spin Pumping and Microwave Photoresistance

We present a method to quantify the spin Hall angle (SHA) with spin pumping and microwave photoresistance measurements. With this method, we separate the inverse spin Hall effect (ISHE) from other unwanted effects for permalloy/Pt bilayers using out-of-plane microwave excitation. Through microwave photoresistance measurements, the in- and out-of-plane precessing angles of the magnetization are determined and enabled for the exact determination of the injected pure spin current. This method is demonstrated with an almost perfect Lorentz line-shape for the obtained ISHE signal and the frequency independent SHA value as predicted by theory. By varying the Pt thickness, the SHA and spin-diffusion length of Pt is quantified as 0.012 (0.001) and 8.3 (0.9) nm, respectively.

cond-mat.mes-hall↗