scholarly journals Coherent ac spin current transmission across an antiferromagnetic CoO insulator

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Q. Li ◽  
M. Yang ◽  
C. Klewe ◽  
P. Shafer ◽  
A. T. N’Diaye ◽  
...  
Keyword(s):  
Spin Current ◽  
Spin Precession ◽  
Fundamental Physics ◽  
Time Resolved ◽  
Pump Probe ◽  
Insulating Layer ◽  
X Ray ◽  
Current Transmission ◽  
Measurement Results ◽  
Probe Measurements

AbstractThe recent discovery of spin current transmission through antiferromagnetic insulating materials opens up vast opportunities for fundamental physics and spintronics applications. The question currently surrounding this topic is: whether and how could THz antiferromagnetic magnons mediate a GHz spin current? This mismatch of frequencies becomes particularly critical for the case of coherent ac spin current, raising the fundamental question of whether a GHz ac spin current can ever keep its coherence inside an antiferromagnetic insulator and so drive the spin precession of another ferromagnet layer coherently? Utilizing element- and time-resolved x-ray pump-probe measurements on Py/Ag/CoO/Ag/Fe75Co25/MgO(001) heterostructures, here we demonstrate that a coherent GHz ac spin current pumped by the Py ferromagnetic resonance can transmit coherently across an antiferromagnetic CoO insulating layer to drive a coherent spin precession of the Fe75Co25 layer. Further measurement results favor thermal magnons rather than evanescent spin waves as the mediator of the coherent ac spin current in CoO.

scholarly journals Direct Detection of Pure ac Spin Current by X-Ray Pump-Probe Measurements

2016 ◽  
Vol 117 (7) ◽  
Author(s):  
J. Li ◽  
L. R. Shelford ◽  
P. Shafer ◽  
A. Tan ◽  
J. X. Deng ◽  
...  
Keyword(s):  
Direct Detection ◽  
Spin Current ◽  
Pump Probe ◽  
X Ray ◽  
Probe Measurements

Resonant soft x-ray scattering endstation for time-resolved pump-probe measurements at LCLS

2012 ◽  
Author(s):  
Yi-De Chuang ◽  
Dionisio Doering ◽  
Alejandro G. Cruz ◽  
Nadeem Tahir ◽  
Nord C. Andresen ◽  
...  
Keyword(s):  
Time Resolved ◽  
Pump Probe ◽  
X Ray ◽  
X Ray Scattering ◽  
Probe Measurements ◽  
Ray Scattering

Pump-Probe Measurements Using Silicon Nanocrystal Waveguides

2003 ◽  
Vol 770 ◽  
Author(s):  
Nathanael Smith ◽  
Max J. Lederer ◽  
Marek Samoc ◽  
Barry Luther-Davies ◽  
Robert G. Elliman
Keyword(s):  
Probe Beam ◽  
Time Resolution ◽  
Pump Beam ◽  
Silicon Nanocrystals ◽  
Continuous Wave ◽  
Optical Gain ◽  
Optical Pump ◽  
Time Resolved ◽  
Pump Probe ◽  
Probe Measurements

AbstractOptical pump-probe measurements were performed on planar slab waveguides containing silicon nanocrystals in an attempt to measure optical gain from photo-excited silicon nanocrystals. Two experiments were performed, one with a continuous-wave probe beam and a pulsed pump beam, giving a time resolution of approximately 25 ns, and the other with a pulsed pump and probe beam, giving a time resolution of approximately 10 ps. In both cases the intensity of the probe beam was found to be attenuated by the pump beam, with the attenuation increasing monotonically with increasing pump power. Time-resolved measurements using the first experimental arrangement showed that the probe signal recovered its initial intensity on a time scale of 45-70 μs, a value comparable to the exciton lifetime in Si nanocrystals. These data are shown to be consistent with an induced absorption process such as confined carrier absorption. No evidence for optical gain was observed.

scholarly journals Time-resolved x-ray/optical pump-probe simulations on N2 molecules

2019 ◽  
Vol 6 (2) ◽  
pp. 024101
Author(s):  
Athiya Mahmud Hanna ◽  
Oriol Vendrell ◽  
Robin Santra
Keyword(s):  
Optical Pump ◽  
Time Resolved ◽  
Pump Probe ◽  
X Ray

scholarly journals Probing Attosecond Electron Coherence in Molecular Charge Migration by Ultrafast X-Ray Photoelectron Imaging

2019 ◽  
Vol 9 (9) ◽  
pp. 1941 ◽  
Author(s):  
Kai-Jun Yuan ◽  
André D Bandrauk
Keyword(s):  
Electron Dynamics ◽  
Charge Migration ◽  
Photoelectron Imaging ◽  
Time Resolved ◽  
Pump Probe ◽  
New Approach ◽  
X Ray ◽  
Chemistry Research ◽  
Molecular Charge ◽  
Electron Coherence

Electron coherence is a fundamental quantum phenomenon in today’s ultrafast physics and chemistry research. Based on attosecond pump–probe schemes, ultrafast X-ray photoelectron imaging of molecules was used to monitor the coherent electron dynamics which is created by an XUV pulse. We performed simulations on the molecular ion H 2 + by numerically solving time-dependent Schrödinger equations. It was found that the X-ray photoelectron angular and momentum distributions depend on the time delay between the XUV pump and soft X-ray probe pulses. Varying the polarization and helicity of the soft X-ray probe pulse gave rise to a modulation of the time-resolved photoelectron distributions. The present results provide a new approach for exploring ultrafast coherent electron dynamics and charge migration in reactions of molecules on the attosecond time scale.

scholarly journals XPP: X-ray Pump Probe station at BESSY II

2016 ◽  
Vol 2 ◽  
Author(s):  
Matthias Reinhardt ◽  
Wolfram Leitenberger
Keyword(s):  
Soft Matter ◽  
Ambient Conditions ◽  
X Ray Diffraction ◽  
Time Resolved ◽  
Pump Probe ◽  
X Ray ◽  
Experimental Station

The X-ray Pump-Probe (XPP) experimental station predominantly aims at investigating hard and soft matter under a broad range of ambient conditions using time-resolved X-ray diffraction.

scholarly journals X-rays only when you want them: optimized pump–probe experiments using pseudo-single-bunch operation

2015 ◽  
Vol 22 (3) ◽  
pp. 729-735 ◽  
Author(s):  
M. P. Hertlein ◽  
A. Scholl ◽  
A. A. Cordones ◽  
J. H. Lee ◽  
K. Engelhorn ◽  
...  
Keyword(s):  
Laser Excitation ◽  
Ccd Camera ◽  
Single Shot ◽  
X Rays ◽  
Time Resolved ◽  
Pump Probe ◽  
Charge Coupled Device ◽  
X Ray ◽  
X Ray Absorption ◽  
Sample Damage

Laser pump–X-ray probe experiments require control over the X-ray pulse pattern and timing. Here, the first use of pseudo-single-bunch mode at the Advanced Light Source in picosecond time-resolved X-ray absorption experiments on solutions and solids is reported. In this mode the X-ray repetition rate is fully adjustable from single shot to 500 kHz, allowing it to be matched to typical laser excitation pulse rates. Suppressing undesired X-ray pulses considerably reduces detector noise and improves signal to noise in time-resolved experiments. In addition, dose-induced sample damage is considerably reduced, easing experimental setup and allowing the investigation of less robust samples. Single-shot X-ray exposures of a streak camera detector using a conventional non-gated charge-coupled device (CCD) camera are also demonstrated.

Design of a fast rotational chopper for X-ray pump–probe experiments at Diamond Light Source

2010 ◽  
Vol 1 (MEDSI-6) ◽  
Author(s):  
Luis Varandas ◽  
Andrew Peach ◽  
Kevin Collins ◽  
Brian Nutter
Keyword(s):  
Single Crystal Diffraction ◽  
Time Resolved ◽  
Pump Probe ◽  
X Ray ◽  
X Ray Crystallography ◽  
Atomic Structures ◽  
Advanced Control ◽  
Speed Stability ◽  
Exceptional Stability ◽  
Energy Activation

New trends in X-ray crystallography are concerned with the study of transient conditions of atomic structures, which take place after an energy activation agent is introduced. These time-resolved experiments require a fast mechanical shutter to interrupt the X-ray beam in a pump–probe cycle, with the aim to generate a stroboscopic effect. Thus, only diffraction data that are representative of the activated structure are actually collected. A rotating type of shutter, also known as chopper, is presented with the purpose to enable time-resolved experiments to be performed at I19 small-molecule single-crystal diffraction beamline. Exceptional stability in the rotational speed is critical to achieve the desired stroboscopic effect with minimum jitter. This requirement can be addressed only through design by the specification of suitable components and implementation of high-precision methods in manufacturing. The proposed equipment is comprised of a spindle supported on air bearings coupled to a slotted disc rotating inside a vacuum enclosure and driven by a brushless servo motor. Advanced control features are proposed to ensure that speed stability is achieved. Preliminary tests produced very encouraging results, giving strong indication that the chopper satisfies the specifications required for time-resolved experiments.

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