In the world of physics, the idea of manipulating magnetism with light has always been fascinating. Traditionally, intense laser pulses have been used to induce changes in the magnetization orientation of materials by heating them up rapidly. However, a recent study conducted by scientists from the Max Born Institute (MBI) has introduced a groundbreaking non-thermal approach to generating significant magnetization changes using circularly polarized pulses of extreme ultraviolet (XUV) radiation.
The conventional methods of using intense laser pulses to impact magnetization rely on the absorption of light energy, which results in the heating of the material and subsequent perturbation of the magnetic order. While these methods have led to exciting phenomena like ultrafast demagnetization and magnetization switching, they also come with the drawback of significant heat load on the material, limiting their practical applications. The team of researchers at MBI introduced a non-thermal pathway that is based on the inverse Faraday effect (IFE), where the interaction between the polarization of the incoming XUV light and the magnetic moments in the material leads to observable magnetization changes without the need for electronic heating.
Experimental Setup
To demonstrate this non-thermal approach, the researchers used a ferrimagnetic iron-gadolinium alloy and exposed it to circularly polarized femtosecond pulses of XUV radiation. The high photon energy of the XUV radiation allowed for resonant excitation of tightly bound core-level electrons in the alloy, resulting in the generation of a strong IFE-induced magnetization. By measuring the difference in ultrafast demagnetization for opposite helicities of the circularly polarized XUV pulses, the researchers were able to quantify the magnitude of the magnetization changes, which could reach up to 20-30% of the ground-state magnetization of the alloy.
The innovative approach introduced by the team at MBI opens up new possibilities in the fields of ultrafast magnetism, spintronics, and coherent magnetization control. By providing a method for generating large magnetization changes on ultrafast timescales without the need for electronic heating, this research paves the way for more efficient and technologically applicable magnetization manipulation techniques. The findings of this study, supported by ab initio theory and spin dynamics simulations, offer a promising avenue for exploring the science of nonlinear X-ray matter interactions and advancing our understanding of opto-magnetic phenomena.
The utilization of circularly polarized XUV radiation for non-thermal magnetization manipulation represents a significant breakthrough in the field of condensed matter physics. The ability to induce substantial magnetization changes in materials without the drawbacks of excessive heat load opens up new avenues for research and technological applications. As researchers continue to explore the potential of opto-magnetic effects, we can expect further advancements in the control and manipulation of magnetism with light.