NSRRC Activity Report 2023

124 NSRRC ACTIVITY REPORT 2023 Two workshops were held on October 26. The events are summarized below: Workshop I: XAS–XMCD of Novel Materials This workshop aimed to gather experts in the field to share recent developments and research results on novel materials exhibiting spin-charge transitions and how XAS–XMCD can be used to investigate their electronic structure and magnetism. In the opening remarks made by Dr. Chia- Hao Chen, recent performance and research output of the XAS–XMCD Dragon Beamline over the past 5 years were presented and the aim of developing a XAS–XMCD user community for the “new Dragon Beamline” TPS 33A , which is one of the TPS Phase-III beamlines, was elucidated. The first session consisted of three well-known speakers: Prof. Pong Way-Faung (Tamkang University), Prof. Jung- Chun Andrew Huang (National Cheng Kung University, NCKU), and Prof. Yin-Hao Chu (NTHU). Prof. Pong discussed the 2D XY Spin glass properties of a perovskite oxide (Ni 1-x Mn x )TiO 3 . This was followed by Prof. Huang’s talk on ferromagnetic Cr 2 Te 3 thin films, emphasizing the importance of 2D magnets for spintronics and opto- spintronic applications. Prof. Chu’s talk focused on the popular research on high-entropy alloys and high-entropy oxides as complex magnets. Subsequently, Prof. Bo-Yao Wang (National Changhua University of Education) elucidated perpendicular magnetic anisotropy induced by antiferromagnetic thin films in antiferromagnet–ferromagnet heterostructures. Dr. Yan- Gu Lin (NSRRC) presented the valuable results acquired recently by his team using XAS for studying electrochemical interfaces. The last talk of the morning was presented by Prof. Yuan-Chieh Tseng (National Yang Ming Chiao Tung University) showing how XAS and XMCD could be used to solve critical problems in ferroelectric semiconductors and spin-orbit torque-based spintronic devices. After the lunch break, the third session consisted of talks on novel magnetic materials and phenomena by three very prolific scientists from NTU. Prof. Chi-Feng Pai highlighted the role of spin-orbit torque in developing memory devices. Prof. Ssu-Yen Huang presented on three important examples of spin-to-charge conversion phenomena and how they provided significant advantages for developing electrically controlled energy-efficient spintronic devices. Prof. Danru Qu presented the concepts of spin-current generation and explained the differences between conventional and unconventional methods of generating pure spin current in ferromagnetic metals. She also showed how pure spin current could be carried by magnons in magnetic insulators, where no charge carriers were required at all. In the last session, Prof. Yi-Ying Chin (National Chung Cheng University) presented her recent work regarding the fundamental issues on cobaltates and cuprates using XAS– XMCD. Dr. Tzu-Hung Chuang (NSRRC) discussed the use of the photoelectron momentum microscope, which is currently under commissioning at TPS 27A , for measuring three dimensional Fermi surfaces. He also presented the spin-resolved imaging capability of the photoelectron momentum microscope. Finally, the last talk by Dr. Wen- Bin Wu (NSRRC) introduced the conceptual design of the new Dragon XAS–XMCD beamline at TPS 33A to the attendees. The concluding remarks were presented by one of the workshop organizers Dr. Ashish A. Chainani. He mentioned that the workshop was successful in highlighting the role of XAS–XMCD studies for future research; he also emphasized that new researchers could play the major role in future research on spintronic, opto-spintronic and memory devices using the XAS–XMCD techniques. Dr. Chainani proposed the formation of a XAS–XMCD user community, who could meet online once every 3 or 6 months. This community will be an open access platform for all users to discuss their need for future experiments at TPS 33A in terms of performance, specification, preferred beam size, energy resolution, temperature, applied field- dependent measurements, sample preparation facilities, etc . Workshop II: Neutron Diffraction and Reflectivity The NSRRC has been devoted to developing synchrotron technology for decades, supporting the applications of synchrotron radiation to academia and industry. In recent years, NSRRC was further supportive of the Neutron Group stationed at the Australian Nuclear Science and Technology Organisation (ANSTO) in Australia, aiming to encouraging research that utilizes neutron scattering technology in Taiwan. In this workshop, eight domestic scholars were invited to share their experience and knowledge on neutron diffraction and neutron reflectometry. First, the Deputy Director of the NSRRC, Dr. Der-Hsin Wei, delivered the opening remarks, followed by presentations by the invited speakers. Prof. Chao-Hung Du (Tamkang University) presented studies on the YBaCu x Fe 1-x O 5 system using neutron diffraction and resonant X-ray scattering techniques. The research concluded that the magnetic order and ferroelectric properties are largely co-related to the ratio and distribution of cations, which can be tuned by the sintering temperature and quenching conditions. Dr. D. Chandrasekhar Kakarla (National Sun Yat-sen University) reported the neutron diffraction results of several samples measured in ANSTO. After the group photo, Prof. Cheng-Ying Chen (National Taiwan Ocean University) presented on kesterite-based solar cell materials. This research confirmed that conversion efficiency decreases