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Indra Backes

Indra Backes


Saarland University


Materials Chemistry


Rebecca Dally

Faculty Sponsor(s): 

Stephen Wilson

Faculty Sponsor's Department: 


Project Title: 


Project Description: 

Spin-½ triangular lattice antiferromagnets have been studied because of their various exotic magnetic ground states. Due to the geometrical frustration of spins in a triangular lattice, each spin isn’t able to satisfy all pairwise magnetic interactions. This can cause ground state degeneracy that may reveal unconventional magnetic properties. The transition to a spin liquid ground state has been of particular interest. Spin-2 triangular lattices have not been studied to the same extent, yet can also show special magnetic ordering, such as the antiferromagnet, α-NaMnO2. Sheets of magnetic Mn3+ ions lie on the ab-plane in a triangular lattice. This material has an ordering temperature of 45 K and deviates from the classical antiferromagnetic case, as no Curie-Weiss behavior is observed. The investigation of the general magnetic characteristics and the composition of α-NaMnO2 are the topic of this research. Phase pure single crystals of α-NaMnO2 were grown by the floating zone technique. ICP-MS (Inductively coupled plasma mass spectrometry) measurements were performed to identify the exact stoichiometry of these crystals. The magnetic properties were measured as a function of temperature and applied magnetic field. Field-cooled and zero field-cooled susceptibility measurements indicate a magnetic transition around 45 K, consistent with previous reports. Our work eventually aims to identify the effect sodium stoichiometry has on the magnetic properties.