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1. Large magnetocapacitance beyond 420% in epitaxial magnetic tunnel junctions with an MgAl2O4 barrier

   https://doi.org/10.1038/s41598-022-11545-6  

   Sato, Kenta; Sukegawa, Hiroaki; Ogata, Kentaro; Xiao, Gang; Kaiju, Hideo (May 2022, Scientific Reports)

   Abstract Magnetocapacitance (MC) effect has been observed in systems where both symmetries of time-reversal and space-inversion are broken, for examples, in multiferroic materials and spintronic devices. The effect has received increasing attention due to its interesting physics and the prospect of applications. Recently, a large tunnel magnetocapacitance (TMC) of 332% at room temperature was reported using MgO-based (001)-textured magnetic tunnel junctions (MTJs). Here, we report further enhancement in TMC beyond 420% at room temperature using epitaxial MTJs with an MgAl₂O₄(001) barrier with a cation-disordered spinel structure. This large TMC is partially caused by the high effective tunneling spin polarization, resulted from the excellent lattice matching between the Fe electrodes and the MgAl₂O₄barrier. The epitaxial nature of this MTJ system sports an enhanced spin-dependent coherent tunneling effect. Among other factors leading to the large TMC are the appearance of the spin capacitance, the large barrier height, and the suppression of spin flipping through the MgAl₂O₄barrier. We explain the observed TMC by the Debye-Fröhlich modelled calculation incorporating Zhang-sigmoid formula, parabolic barrier approximation, and spin-dependent drift diffusion model. Furthermore, we predict a 1000% TMC in MTJs with a spin polarization of 0.8. These experimental and theoretical findings provide a deeper understanding on the intrinsic mechanism of the TMC effect. New applications based on large TMC may become possible in spintronics, such as multi-value memories, spin logic devices, magnetic sensors, and neuromorphic computing. 

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2. JWST and Ground-based Observations of the Type Iax Supernovae SN 2024pxl and SN 2024vjm: Evidence for Weak Deflagration Explosions

   https://doi.org/10.3847/2041-8213/adf062  

   Kwok, Lindsey A; Singh, Mridweeka; Jha, Saurabh W; Blondin, Stéphane; Dastidar, Raya; Larison, Conor; Miller, Adam A; Andrews, Jennifer E; Andrews, Moira; Anupama, G C; et al (August 2025, The Astrophysical Journal Letters)

   Abstract We present panchromatic optical + near-infrared (NIR) + mid-infrared (MIR) observations of the intermediate-luminosity Type Iax supernova (SN Iax) 2024pxl and the extremely low-luminosity SN Iax 2024vjm. JWST observations provide unprecedented MIR spectroscopy of SN Iax, spanning from +11 to +42 day past maximum light. We detect forbidden emission lines in the MIR at these early times while the optical and NIR are dominated by permitted lines with an absorption component. Panchromatic spectra at early times can thus simultaneously show nebular and photospheric lines, probing both inner and outer layers of the ejecta. We identify spectral lines not seen before in SN Iax, including [Mgii] 4.76μm, [Mgii] 9.71μm, [Neii] 12.81μm, and isolated Oi2.76μm that traces unburned material. Forbidden emission lines of all species are centrally peaked with similar kinematic distributions, indicating that the ejecta are well mixed in both SN 2024pxl and SN 2024vjm, a hallmark of pure deflagration explosion models. Radiative transfer modeling of SN 2024pxl shows good agreement with a weak deflagration of a near-Chandrasekhar-mass white dwarf, but additional IR flux is needed to match the observations, potentially attributable to a surviving remnant. Similarly, we find SN 2024vjm is also best explained by a weak deflagration model, despite the large difference in luminosity between the two supernovae. Future modeling should push to even weaker explosions and include the contribution of a bound remnant. Our observations demonstrate the diagnostic power of panchromatic spectroscopy for unveiling explosion physics in thermonuclear supernovae. 

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3. TMC: Pay-as-you-Go Distributed Communication

   https://doi.org/10.1145/3343180.3343194  

   Demoulin, Henri Maxime; Vasilakis, Nikos; Sonchack, John; Pedisich, Isaac; Liu, Vincent; Loo, Boon Thau; Phan, Linh Thi; Smith, Jonathan M.; Zhang, Irene (August 2019, Proceedings of the 3rd Asia-Pacific Workshop on Networking 2019)

   We revisit the gap between what distributed systems need from the transport layer and what protocols in wide deployment provide. Such a gap complicates the implementation of distributed systems and impacts their performance. We introduce Tunable Multicast Communication (TMC), an abstraction that allows developers to easily specialize communication channels in distributed systems. TMC is presented as a deployable and extensible user-space library that exposes high-level tunable guarantees. TMC has the potential of improving the performance of distributed applications with minimal-to-zero development and deployment effort. 

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4. TMC: Tunable Multicast Communication

   Demoulin, H. M.; Vasilakis, N.; Sonchack, J.; Pedisich, I.; Liu, V.; Loo, B. T.; Phan, L. T.; Smith, J. M.; Zhang, I. (August 2019, 3rd Asia-Pacific Workshop on Networking (APNET))

   We revisit the gap between what distributed systems need from the transport layer and what protocols in wide deployment provide. Such a gap complicates the implementation of distributed systems and impacts their performance. We introduce Tunable Multicast Communication (TMC), an abstraction that allows developers to easily specialize communication channels in distributed systems. TMC is presented as a deployable and extensible user-space library that exposes high-level tunable guarantees. TMC has the potential of improving the performance of distributed applications with minimal-to-zero development and deployment effort. 

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5. Ground-based and JWST Observations of SN 2022pul. II. Evidence from Nebular Spectroscopy for a Violent Merger in a Peculiar Type Ia Supernova

   https://doi.org/10.3847/1538-4357/ad2c0d  

   Kwok, Lindsey_A; Siebert, Matthew_R; Johansson, Joel; Jha, Saurabh_W; Blondin, Stéphane; Dessart, Luc; Foley, Ryan_J; Hillier, D_John; Larison, Conor; Pakmor, Rüdiger; et al (April 2024, The Astrophysical Journal)

   Abstract We present an analysis of ground-based and JWST observations of SN 2022pul, a peculiar “03fg-like” (or “super-Chandrasekhar”) Type Ia supernova (SN Ia), in the nebular phase at 338 days postexplosion. Our combined spectrum continuously covers 0.4–14μm and includes the first mid-infrared spectrum of a 03fg-like SN Ia. Compared to normal SN Ia 2021aefx, SN 2022pul exhibits a lower mean ionization state, asymmetric emission-line profiles, stronger emission from the intermediate-mass elements (IMEs) argon and calcium, weaker emission from iron-group elements (IGEs), and the first unambiguous detection of neon in a SN Ia. A strong, broad, centrally peaked [Neii] line at 12.81μm was previously predicted as a hallmark of “violent merger” SN Ia models, where dynamical interaction between two sub-M_Chwhite dwarfs (WDs) causes disruption of the lower-mass WD and detonation of the other. The violent merger scenario was already a leading hypothesis for 03fg-like SNe Ia; in SN 2022pul it can explain the large-scale ejecta asymmetries seen between the IMEs and IGEs and the central location of narrow oxygen and broad neon. We modify extant models to add clumping of the ejecta to reproduce the optical iron emission better, and add mass in the innermost region (<2000 km s⁻¹) to account for the observed narrow [Oi]λλ6300, 6364 emission. A violent WD–WD merger explains many of the observations of SN 2022pul, and our results favor this model interpretation for the subclass of 03fg-like SNe Ia. 

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