A brief history of low dimensional magnetism: How neutron scattering can reveal novel magnetic states in these exotic materials.

Speaker: Dr Kirrily Rule
Affiliation: Australian Nuclear Science and Technology Organisation

Abstract

Magnetism is ubiquitous to our lives with many technologies relying on the often-complex interplay of magnetic spins in strongly correlated electronic materials. From magnetic memories, microwave oscillators and modulators to sensors, logic gates and transistors, an understanding of the underlying physics is critical to improving these technologies. When the magnetism is confined to a reduced dimensionality, either via physical form (eg thin films or nanoparticles) or through separation via non-magnetic elements, the physical properties can be greatly altered, leading to exotic ground states and novel magnetic properties. Quantum magnetic ions (typically those with S < 1) contribute additional complexities to low dimensional systems and can reveal unusual magnetic states such as Bose Einstein condensation, spin-nematic behaviour, and frustrated spin liquids. Inelastic neutron scattering provides a unique and direct probe to unveil the delicate balance between competing interactions and anisotropies. Through neutron scattering, complex phases in these magnetic materials may be explored by perturbing each system with temperature and magnetic field. Combining experimental data with robust models allows us to understand the nature of the magnetism and the potential applications such spin structures can afford. This talk will discuss the history of low dimensional magnetism and introduce a number of neutron scattering techniques available at ANSTO for magnetism research. Finally, I will show some recent neutron scattering results from materials such as linarite [1,2], and atacamite [3]. [1] K.C. Rule et al., Physical Review B 95, 024430 (2017) [2] L. Heinze et al., arXiv:2204.13482 (2022) [3] L. Heinze et al., Physical Review Letters 126, 207201 (2021)