Principal Investigator :

Oleksiy Drachenko ()
LNCMI (MEGAGAUSS)

Type of project : Disruptive Project

Date (start/end) : 2015 - 2017

     

      

Abstract

In this project we plan to develop a novel THz magneto-spectroscopy setup to be used under the extreme conditions of our semi-destructive (explosive) Megagauss magnetic fields facility, and then to use this unique installation to study fundamentals of SiMn high-temperature ferromagnetism. THz spectroscopy becomes particularly challenging when ultra-fast semi-destructive magnetic fields are in use. This is because, in addition to the usual problems of the THz spectral region (lack of powerful sources and sensitive detectors), the ultrafast timescale of Megagauss fields imposes strict requirements on the detector bandwidth (>100MHz), while the strong electromagnetic pulse accompanying the magnetic field pulse adversely affects any type of electrically-operated devices. In this project we will study different approaches to overcome these limitations. The setup will be used for the measurement of ultra-heavy carrier masses in magnetic semiconductors, up to ~3m ₀ , and it will allow the study of a variety of other modern material systems.

Scientifically, our interest will be primarily focused on studies of high temperature ferromagnetism in MnSix. Generally, the transition metal silicides are an important class of intermetallics, with a large variety of interesting scientific and technological properties. In particular, the higher manganese silicide MnSi _2-x material system has recently attracted considerable attention due to the discovery of a low-current-density spin-torque transfer effect. Additionally, this material looks quite promising for spintronic device applications due to its compatibility with the well-established silicon technology. However, in spite of significant efforts world-wide, materials which simultaneously present high spin polarization of carriers and a high Curie temperature were not evidenced yet. In this project we will study the effective mass in set of MnSi samples via direct cyclotron resonance measurements, in order to understand defect-induced changes in the electronic properties of MnSi alloys.