Excellence in Research: Investigation of novel spin textures in non-centrosymmetric magnetic materials

Non-Technical abstract
In most solids, for every atom within the unit cell at position (x,y,z) there is an indistinguishable atom at (-x,-y,-z). These materials are called centrosymmetric materials. However, magnetic materials where the centrosymmetry is broken, termed noncentrosymmetric materials, have attracted considerable attention in recent years owing to their potential for future nanometer-scale quantum-information technology applications. The aim of this project is to study the fundamental spin and lattice properties of noncentrosymmetric magnets using neutron scattering technique. Neutron scattering is a powerful probe that can determine the spin arrangements of the noncentrosymmetric materials, which will allow their potential use for future applications. The planned research will also train the next generation of graduate and undergraduate students at Prairie View A&M University (PVAMU) for neutron scattering measurements and data analysis. In addition, students will learn how to grow single crystals and basic laboratory skills in low-temperature physics. The joint efforts by combining the strength of PVAMU, Norfolk State University, and Rice University will develop an internationally competitive program involving both the growth of novel complex materials and neutron scattering.

Technical abstract
This project focuses on the synthesis and characterization of non-centrosymmetric magnetic materials such as ScTMGe (TM = Fe, Mn, Co, Ni, Cu), Mn-doped ScFeGe, and chiral magnetic oxides. Both end members ScFeGe and ScMnGe crystallize in hexagonal crystal structure having P-62m space group. ScFeGe is an itinerant helimagnetic system below ~36 K with wavevector k = (0 0 0.193) and a magnetic moment ≈ 0.53 μB confined to the ab plane. A metamagnetic transition is observed with a threshold field of ≈ 6.6 T when H is parallel to the ab plane. The main element of this research plan is the preparation of the above listed materials in polycrystalline form and high-quality single crystals, followed by characterization of their physical properties, including determination of structure, phase purity and the measurement of their electronic, and magnetic properties. The experimental results obtained from this research will unveil the interrelationships between structural and magnetic properties of materials. The samples are synthesized at Prairie View, Rice, and Norfolk State University, followed by characterization of their physical properties, including determination of structure, and the measurement of their electronic, and magnetic properties.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

Award Number: 2602145
Principal Investigator: Sunil Karna
Funds Obligated: $519,949
State: VA