on 02-06-2023
Daigo Oue and Mário Silveirinha are organising a Seminar on different aspects of spintronics in 2D and 3D materials. The Seminar will have three invited speakers, respectively:
Program:
15:00 -15:20
Yuichi Saito (Lancaster University)
"MIR-induced antiferromagnetic spin dynamics at room temperature"
Growing nonlinear optics technology, the sub-picosecond laser pulse has extended its wavelength to the mid-infrared (MIR) band (~20um), where ionic vibrations and molecular oscillations broadly exist. For magnetism, this technology enables us to explore lattice-spin interaction directly, such as phonon-induced magnons. At the seminar, we will report the MIR pump - NIR probe result of a canted ferromagnetic material called FeBO3 and discuss the optical absorbance and magnon amplitude spectrum.
15:20 - 15:40
Junta Igarashi (Institute Jean Lamour, Université de Lorraine)
"Sub-picosecond magnetization manipulation induced by ultrafast-spin transfer"
The manipulation of magnetic materials without the use of magnetic fields is of great fundamental and technical interest. The discovery of spin-transfer torque (STT) allowed us to control the magnetization direction electrically in magnetic devices within nanoseconds, which paved the way for non-volatile applications such as spin-transfer- torque magnetoresistive random access memory (STT-MRAM). However, current-induced STT switching below a few hundred picoseconds with low power consumption while maintaining high thermal stability is still challenging. Ultra-short optical pulses can also be used to manipulate the magnetization direction without a magnetic field, which is called all-optical switching (AOS). So far, only specific materials containing ferrimagnet such as GdFeCo have shown ultrafast AOS. Thus, these methods to manipulate magnetization have been mostly developed independently within the fields of spintronics and ultrafast magnetism. In this seminar, I will show our recent work, where we demonstrated sub-picosecond magnetization reversal of a Co/Pt ferromagnetic layer induced by a single femtosecond laser pulse within a common [Co/Pt]/Cu/[Co/Pt] perpendicular spin-valve structure.
15:40 -16:00
Shuichi Iwakiri (ETH Zürich)
"Gate-defined quantum interferometer in magic-angle twisted bilayer graphene"
Magic-Angle Twisted Bilayer Graphene (MATBG) hosts a variety of quantum states, such as superconductivity and correlated insulating phases, which are tunable via gating. The mechanism of these correlated phenomena has been the subject of active theoretical and experimental research.
In this talk, I will present the fabrication and measurement of gate-defined devices to observe quantum interferences in MATBG, such as SQUID and Little-Parks oscillations. These devices are expected to be a powerful tool for elucidating Cooper pair symmetry and, ultimately, the mechanism of superconductivity.
The Seminar will take place on Friday (2nd June), from 15:00 to 16:00, in the Meeting Room, 11th Floor, Torre Norte, Instituto Superior Técnico, Lisboa, Portugal.