A compact cryogenic Kerr microscope for operation in the small volume of high-field magnets is described. It is suited for measurements both in Voigt and Faraday configurations. Coupled with a pulsed laser source, the microscope is used to measure the time-resolved Kerr rotation response of semiconductor microstructures with approximately 1 mum spatial resolution. The microscope was designed to study spin transport, a critical issue in the field of spintronics. It is thus possible to generate spin polarization at a given location on a microstructure and probe it at a different location. The operation of the microscope is demonstrated by time-resolved measurements of micrometer distance diffusion of spin polarized electrons in a GaAs/AlGaAs heterojunction quantum well at 4.2 K and 7 T.
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http://dx.doi.org/10.1063/1.3046283 | DOI Listing |
Microsc Res Tech
December 2024
University of Science and Technology of China, Hefei, People's Republic of China.
Atomically resolved scanning tunneling microscope (STM) capable of in situ rotation in a narrow magnet bore has become a long-awaited but challenging technique in the field of strong correlation studies since it can introduce the orientation of the strong magnetic field as a control parameter. This article presents the design and functionality of a piezoelectrically driven rotatable STM (RSTM), operating within a 12 T cryogen-free magnet and achieving a base temperature below 1.8 K, along with spectroscopic capabilities.
View Article and Find Full Text PDFSci Adv
December 2024
Universite Claude Bernard Lyon 1, CNRS, ENS Lyon, CRMN UMR 5082, 69100 Villeurbanne, France.
Sensitivity is often the Achilles' heel of liquid-state nuclear magnetic resonance (NMR) experiments. This problem is perhaps most pressing at the lowest fields (e.g.
View Article and Find Full Text PDFNano-positioning plays a very important role in applications such as scanning probe microscopy and optics. We report the development of a compact inertial nanopositioner along with fully computer interfaced electronics operating down to 2 K and its use in our fully automated needle-anvil type Point Contact Andreev Reflection (PCAR) apparatus. We also present the fully automated operational procedures using the LabVIEW interface with our home-built electronics.
View Article and Find Full Text PDFCryogenic trapped-ion systems (CTISs) have emerged as indispensable platforms for the advancement of quantum computation and precision measurement techniques. However, the sensitivity of these systems to vibrational noise, especially during the compression and expansion cycles of the cold head in a Gifford-McMahon cycle refrigerator (GMCR), poses a significant challenge. To mitigate this, we have crafted an innovative methodology for characterizing low-frequency residual vibrational noise in closed-cycle cryogenic trapped-ion systems.
View Article and Find Full Text PDFPhys Rev E
October 2024
General Atomics, San Diego, California 92121, USA.
This paper presents a simple physics-based model for the interpretation of key metrics in laser direct drive. The only input parameters required are target scale, in-flight aspect ratio, and beam-to-target radius, and the importance of each has been quantified with a tailored set of cryogenic implosion experiments. These analyses lead to compact and accurate predictions of the fusion yield and areal density as a function of hydrodynamic stability, and they suggest new ways to take advantage of direct drive.
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