Interfacial roughness driven manipulation of magnetic anisotropy and coercivity in ultrathin thulium iron garnet films

We have investigated the magnetic properties of thulium iron garnet (Tm3Fe5O12, TmIG) thin films grown on {111} gadolinium gallium garnet (Gd3Ga5O12, GGG) substrates fabricated via the facing target sputtering method. The annealing temperature (T-a), thickness (t(f)), and roughness were systematically controlled in order to obtain the perfect magnetic properties of the film showing perpendicular magnetic anisotropy (PMA) and large coercive field, which are the requisites for non-volatile magnetic memory device applications. Here, we demonstrated that the T-a acts as the crucial parameter both for obtaining the high quality of the film surface and engineering the direction of the magnetic anisotropy from the in-plane to out-of-plane. Through the further optimization process with a function of the t(f), we successfully achieved the best condition for the PMA films. Specifically, the sample fabricated at a t(f) of 20 nm and T-a of 1000 degrees C showed the perfect PMA. Furthermore, the surface roughness of the substrate mainly contributes to the enhancement of the coercive field of the perpendicular magnetic anisotropic films. We speculate that the drag force from the pinning energy induced by the interfacial roughness retarded the domain wall motion at the TmIG/GGG interface, resulting in enhanced coercivity. (C) 2022 Elsevier B.V. All rights reserved

The Korean War Veterans Memorial and Problems of Representation

This article examines the design history of the Korean War Veterans Memorial dedicated in Washington DC in 1995. It considers the attempt to achieve demographic inclusiveness by representing figures of every ethnic group in the sculptural depiction of the U.S. troops in Korea. It interprets this commemorative approach as an extension of the principle established in the commemoration of the Vietnam War in the 1980s, in which the norm of multifigure sculptural groups was intended to achieve the goal of demographic inclusiveness. The Korea memorial was also a response to the preference, particularly among right-wing, pro-military veterans, for commemorations consisting of realistic sculpture; the large number of figures (nineteen, making this an extremely large statuary group) allowed each of the four major armed services to be represented, and the inscribed pictorial wall allowed even more figures, representing each military specialist group, to be portrayed. In this way, the Korea memorial answered criticisms levelled at Vietnam War commemorations which generally concentrated on the depiction of foot soldiers. The essay’s argument places the creation of the multi-figure Korean War Veterans Memorial statuary group into the recent history of commemorative sculpture, but also contrasts it with a longer tradition, marked in the period from around 1890 to 1930, in which Washington was the site for other kinds of commemorative sculpture, including portrait statuary, historical works, and allegorical forms. The essay suggests that the shift to a kind of dumb literalism has involved a loss in the language of public sculpture. It advocates a rediscovery and reinvention of the language of symbolism following the extensio ad absurdum of the tendency to demographic and interest-group inclusiveness in the Korean War Veterans Memorial

Recent Advances in Triboelectric Nanogenerators: From Technological Progress to Commercial Applications.

Serious climate changes and energy-related environmental problems are currently critical issues in the world. In order to reduce carbon emissions and save our environment, renewable energy harvesting technologies will serve as a key solution in the near future. Among them, triboelectric nanogenerators (TENGs), which is one of the most promising mechanical energy harvesters by means of contact electrification phenomenon, are explosively developing due to abundant wasting mechanical energy sources and a number of superior advantages in a wide availability and selection of materials, relatively simple device configurations, and low-cost processing. Significant experimental and theoretical efforts have been achieved toward understanding fundamental behaviors and a wide range of demonstrations since its report in 2012. As a result, considerable technological advancement has been exhibited and it advances the timeline of achievement in the proposed roadmap. Now, the technology has reached the stage of prototype development with verification of performance beyond the lab scale environment toward its commercialization. In this review, distinguished authors in the world worked together to summarize the state of the art in theory, materials, devices, systems, circuits, and applications in TENG fields. The great research achievements of researchers in this field around the world over the past decade are expected to play a major role in coming to fruition of unexpectedly accelerated technological advances over the next decade

Recent advances in triboelectric nanogenerators: from technological progress to commercial applications

Serious climate changes and energy-related environmental problems are currently critical issues in the world. In order to reduce carbon emissions and save our environment, renewable energy harvesting technologies will serve as a key solution in the near future. Among them, triboelectric nanogenerators (TENGs), which is one of the most promising mechanical energy harvesters by means of contact electrification phenomenon, are explosively developing due to abundant wasting mechanical energy sources and a number of superior advantages in a wide availability and selection of materials, relatively simple device configurations, and low-cost processing. Significant experimental and theoretical efforts have been achieved toward understanding fundamental behaviors and a wide range of demonstrations since its report in 2012. As a result, considerable technological advancement has been exhibited and it advances the timeline of achievement in the proposed roadmap. Now, the technology has reached the stage of prototype development with verification of performance beyond the lab scale environment toward its commercialization. In this review, distinguished authors in the world worked together to summarize the state of the art in theory, materials, devices, systems, circuits, and applications in TENG fields. The great research achievements of researchers in this field around the world over the past decade are expected to play a major role in coming to fruition of unexpectedly accelerated technological advances over the next decade