People

Dr. Jia-Yush Yen, President of National Taiwan University of Science and Technology: NTUST is Deeply Engaged in Research and Development to Cultivate Innovative and Entrepreneurial Talents [ 下載 PDF ]

Claire Lin

Magnetic Materials & Related Technological Applications

Magnetic Materials & Related Technological Applications—Recent Development and Challenge of Magneto-resistive Random Access Memory [ 下載 PDF ]

Yuan-Chieh Tseng, Kuan-Ming Chen

With the rapid development of the semiconductor industry, the progress of transistor miniaturization is made rapidly. Even though the physical limits are approaching, major research teams are still diligently exploring various possibilities. However, memory technology is not as good at miniaturization as it should be, so there is a demand for new memory, one of which is magneto-resistive random access memory (MRAM). MRAM has non-volatile properties, with fast read/write speed, and high overwriting frequency. These merits make it a promising candidate for next-generation memory technology. However, there are considerable challenges in MRAM in terms of the fabrication process. In this report, we explore the development and bottlenecks of this technology, first from the perspective of spin-transfer torque (STT) MRAM. We then extend to the spin-orbit torque (SOT) MRAM, which is a very popular research topic of the technology.

The Next Generation Magnetic Random—Access Memory: The Opportunities and Challenges [ 下載 PDF ]

Po-Wei Lee, Po-Hung Lin, Chih-Huang Lai

The magnetic random access memory (MRAM) that utilizes the spin-orbit torque as the writing method possess a lot of advantages. Faster writing speed, lower power consumption and higher endurance are its merits. Thus it is a highly potential candidate for the next-generation non-volatile memory. In this article, we will introduce the advantages and working principle of MRAM, how to generate the spin-orbit torque and how it switches the magnetic moment. The main challenges for the development of next generation SOT-MRAM are two folds: how to switch the magnetic moment without the external magnetic field and how to further reduce the switching current. Finally, besides its application for memory, we talk about its applications on the multi-level storage and neuromorphic computing.

Spin-to-charge Conversion in Topological Insulator [ 下載 PDF ]

Jung-Chun-Andrew Huang

This article introduces several important concepts in spintronics such as charge current, polarized current and spin current, the mechanism of spin current generation and detection, and spin-to-charge conversion. A novel material, topological insulator, is also introduced. In the heterostructures of topological insulator and magnetic materials, we adjust the Fermi level to tune the spin-to-charge conversion. Through spin pumping study, the dependence of spin-to-charge conversion on the Fermi level of topological insulators is revealed. The results show that when the Fermi energy approaches the Dirac point, a spin current can be transformed into a charge current to the greatest extent. Our research work provides a new method to achieve effective spin-to-charge conversion by controlling the Fermi level of topological insulators. Spin-to-charge conversion is a very important subject and key technology for the reading and writing functions of spintronic devices, as well as for the development of low-energy consumption and high-speed devices.

The Influence of Spin Fluctuation and Demagnetization Effect on Manipulating Spin Current [ 下載 PDF ]

Po-Hsun Wu, Ssu-Yen Huang

A pure spin current can more efficiently deliver spin angular momentum with fewer or no charge carriers. Therefore, spintronic phenomena and devices have evolved from exploiting spinpolarized current to pure spin current. Here, we demonstrate spin fluctuations in the spin-glass system can enhance the pure spin current. Furthermore, we show that the shape of specimens and demagnetizing effects strongly influence the manipulation of pure spin current.

Low-temperature High-field X-ray Absorption Spectroscopies [ 下載 PDF ]

Yi-Ying Chin

In this manuscript, the X-ray absorption spectroscopy studies on BaCoO₃ and TbFe₃(BO₃)₄ under high magnetic field are briefly introduced. For BaCoO₃, the effective magnetic moment (2.23 μ_B) extracted from the magnetic susceptibility is larger than 1.73 μ_B (the value without any orbital moment), while its crystal structure prefers the hole occupation of the a1g orbital with m = 0. Combining the X-ray magnetic circular dichroism and theoretical calculations, we found that the short distance between Co ions along the c axis makes the a1g orbital lower in energy and thus leads to the finite orbital moment. On the other hand, we employed X-ray linear dichroism to determine the antiferromagnetic structure of TbFe₃(BO₃)₄ and performed experiments under various magnetic field to investigate the significant enhancement of the magnetization in the antiferromagnetic phase.

Column

Application of Self-powered Systems in Environmental and Biological Disinfection [ 下載 PDF ]

Hsuan-Yu Ho, Yu-Ying Cheng, Hsin-Hsuan Ho, Zong-Hong Lin

"Disinfection" is crucial in our daily life, especially during this pandemic time. In addition to frequent hand washing to maintain personal hygiene, environmental cleanliness is also extremely important. However, traditional disinfection methods have drawbacks such as toxicity, low biocompatibility, energy consumption, and low efficiency. Therefore, there is an urgent need to develop low-toxicity, environmentally-friendly and effective disinfection technologies. Our team utilizes thermoelectric materials, optical/piezoelectric materials, and triboelectric nanogenerators to fabricate different types of disinfection devices. These three devices achieve the disinfection effect by respectively converting temperature, light, and mechanical energy from the environment to produce electroporation or generate reactive oxygen species.

Popular Science

Evolving Advanced Intelligent Manufacturing: The Intelligent Manufacturing Platform of TIRI [ 下載 PDF ]

Chien-Yao Huang

Taiwan Instrument Research Institute (TIRI) of National Applied Research Laboratories (NARLabs) is a provider of the customized advanced instrument research and development platform required for innovative domestic research. Over the years, it has been committed to helping industry, academia, and research circles develop various advanced instruments and equipment. TIRI᾿s outstanding contributions can be found in areas from the optical payload of space remote-sensing satellites to the deep-sea hyperspectral system. In recent years, in addition to its development of intelligent manufacturing technology, TIRI has been, by providing its facilities, assisting academic and research circles in verifying developed sensors and related intelligent manufacturing technology. By so doing, TIRI has helped to accelerate the application of technology in the field. This article summarizes the application results of intelligent manufacturing technology developed by TIRI and the academic research teams participating in the platform in recent years. It is expected that more academic and research teams will realize their innovations through the
assistance of TIRI in the future.