Title: Small Moment Antiferromagnetic Ordering in Single Crystalline La2Ni7
When: Thursday, March 30, (2023), 12:00
Place: Department of Condensed Matter Physics, Faculty of Sciences, Module 3, Seminar Room (5th Floor).
Speaker: Raquel Ribeiro, Ames Lab and Iowa State University, USA.
Specific heat, electrical resistivity, and low field magnetization measurements indicate that there is a series of antiferromagnetic phase transitions in La2Ni7 single crystals. They have very small entropy changes associated with them and the anisotropic M(H) data saturatestrongly suggesting the AFM order is associated with very small, itinerant, moments. Our data allow for the construction of anisotropic H-T phase diagrams as well as the identification of the two lower temperature magnetic states as antiferromagnetically ordered, with the moments aligned along the c-axis, and the higher temperature, state as having a finite ferromagnetic component. Neutron diffraction studies have found the propagation vectors and magnetic moment directions of the three magnetically ordered phases, two incommensurate and one commensurate, as a function of temperature. ARPES data reveal several electron and hole pockets that have hexagonal symmetry near the Γ point. The experimental data are in a reasonable agreement with DFT calculations, demonstrating their applicability to itinerant antiferromagnet systems. Our results detail the effects of magnetic ordering on the electronic structure in a Ni-based weak antiferromagnetic.