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Full-Text Articles in Physics

Direct Current Magnetic Hall Probe Technique For Measurement Of Field Penetration In Thin Film Superconductors For Superconducting Radio Frequency Resonators, Iresha Harshani Senevirathne, Alex Gurevich, Jean Delayen Jan 2022

Direct Current Magnetic Hall Probe Technique For Measurement Of Field Penetration In Thin Film Superconductors For Superconducting Radio Frequency Resonators, Iresha Harshani Senevirathne, Alex Gurevich, Jean Delayen

Physics Faculty Publications

Superconducting Radio Frequency (SRF) cavities used in particle accelerators are typically formed from or coated with superconducting materials. Currently, high purity niobium is the material of choice for SRF cavities that have been optimized to operate near their theoretical field limits. This brings about the need for significant R & D efforts to develop next generation superconducting materials that could outperform Nb and keep up with the demands of new accelerator facilities. To achieve high quality factors and accelerating gradients, the cavity material should be able to remain in the superconducting Meissner state under a high RF magnetic field without …


Studying The Interface Between Croconic Acid Thin Films And Substrates Using A Slow Positron Beam, Dean Peterson, Jiandang Liu, Jonas Etzweiler, Gabriel Sontoyo, Sara J. Callori, Kimberley R. Cousins, Timothy Usher, Renwu Zhang Jan 2019

Studying The Interface Between Croconic Acid Thin Films And Substrates Using A Slow Positron Beam, Dean Peterson, Jiandang Liu, Jonas Etzweiler, Gabriel Sontoyo, Sara J. Callori, Kimberley R. Cousins, Timothy Usher, Renwu Zhang

Physics Faculty Publications

Croconic acid (CA) is the first organic ferroelectric with a spontaneous polarity in bulk samples comparable to its inorganic counterparts. As a natural extension of study, ultrathin CA films (∼nm scale) were investigated to reveal ferroelectric effects in films on different substrates for their fundamental and industrial significance. However, the void defect at the interface between the film and substrate is presumed to interfere with surface effects. In this work, a non-invasive technique, a slow positron beam, coupled with Doppler broadening energy spectroscopy (DBES), is applied to study the void defects within the interfacial layer between CA films and Si …


Interface‐Coupled Bifeo3/Bimno3 Superlattices With Magnetic Transition Temperature Up To 410 K, Eun-Mi Choi, Josée E. Kliebeuker, Thomas Fix, Jie Xiong, Christy J. Kinane, Dario Arena, Sean Langridge, Aiping Chen, Zhenxing Bi, Joon Hwan Lee, Quanix Jia, Mark G. Blamire, Judith L. Macmanus-Driscoll Mar 2016

Interface‐Coupled Bifeo3/Bimno3 Superlattices With Magnetic Transition Temperature Up To 410 K, Eun-Mi Choi, Josée E. Kliebeuker, Thomas Fix, Jie Xiong, Christy J. Kinane, Dario Arena, Sean Langridge, Aiping Chen, Zhenxing Bi, Joon Hwan Lee, Quanix Jia, Mark G. Blamire, Judith L. Macmanus-Driscoll

Physics Faculty Publications

Enhanced magnetic transition temperatures are demonstrated in 50 nm thick (001)‐oriented (BiFeO3)m/(BiMnO3)m (BFO/BMO) superlattices (SL). Highly strained ultra‐short SLs showed a magnetic transition, TC2, up to ≈410 K as a result of ferrimagnetic interaction between BFO/BMO. All SL showed a new ferromagnetic transtion, TC1, of ≈150 K coming from Fe4+‐Fe4+ interaction explained by electron transfer/leakage from Fe3+ to Mn3+.


Maximum Screening Fields Of Superconducting Multilayer Structures, Alex Gurevich Jan 2015

Maximum Screening Fields Of Superconducting Multilayer Structures, Alex Gurevich

Physics Faculty Publications

It is shown that a multilayer comprised of alternating thin superconducting and insulating layers on a thick substrate can fully screen the applied magnetic field exceeding the superheating fields Hsof both the superconducting layers and the substrate, the maximum Meissner field is achieved at an optimum multilayer thickness. For instance, a dirty layer of thickness ~0.1μm at the Nb surface could increase Hs similar or equal to 240 mT of a clean Nb up to Hs similar or equal to 290 mT. Optimized multilayers of Nb3Sn, NbN, some of the iron pnictides, or alloyed …


Summary Of The Workshop On The Applications Of X-Ray Standing Waves In Studies Of Surfaces, Fiims, And Buik Materiais, David R. Heskett, L. Berman Feb 1995

Summary Of The Workshop On The Applications Of X-Ray Standing Waves In Studies Of Surfaces, Fiims, And Buik Materiais, David R. Heskett, L. Berman

Physics Faculty Publications

Highlights of the satellite workshop on the technique of x-ray standing waves which preceded the 5th International Conference on Synchrotron Radiation Instrumentation held at the State University of New York at Stony Brook, USA are presented. At the workshop, many applications of the x-ray standing-wave technique were described in both invited and contributed talks. While the predominant use of the XSW technique was to analyze the structure of adsorbates on surfaces, applications in the characterization of thin films, interfaces, clean surfaces, and bulk materials were also presented. Most of the talks concentrated on experimental results, but some theory was also …


Review Of Hall Effect And Magnetoresistance Measurements In Gaas Materials And Devices, David C. Look Jan 1990

Review Of Hall Effect And Magnetoresistance Measurements In Gaas Materials And Devices, David C. Look

Physics Faculty Publications

The use of magnetic fields in the electrical characterization of semiconductor materials is familiar to everyone in the form of Hall‐effect measurements. However, there is another magnetic‐field‐based phenomenon, magnetoresistance (MR), which is highly useful but not nearly so familiar to the majority of workers. One of the unique features of MR measurements is their applicability to common device structures, in particular, field‐effect transistors (FETs) and contact‐resistance patterns. We will show how channel mobility information can be extracted from the MR data in metal‐semiconductor FETs (MESFETs) and modulation‐doped heterostructure FETs (MODFETs), and also how the material under ohmic contacts can be …