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Di Peng – Antiferromagnetic order and possible quantum spin liquid in sodium doped 2,2′-bipyridine
2019-11-07 @ 16:45 - 17:15
Antiferromagnetic order and possible quantum spin liquid in sodium doped 2,2′-bipyridine
Di Peng
Center for High Pressure Science and Technology Advanced Research, Shanghai 201203, China
Organic molecular solids with correlated electronics based on π-electron networks provide fertile ground for the search for peculiar materials, including antiferromagnetic and quantum magnetism. We report a development method for doping alkali metals into organic materials and forming a homogeneous phase together with the experimental discoveries of two antiferromagnetic phase in sodium doped 2,2′-bipyridine at different molar ratios. An antiferromagnetic phase of 160 K is found in sodium-doped 2,2′-bipyridine with a molar ratio of less than 1:1. Another antiferromagnetic phase with Neel temperature of 25 K is observed in samples with molar ratios of 1:1 and 1:2. Applying magnetic field can slowly suppress the 160 K antiferromagnetic phase, while the 25 K antiferromagnetic phase is insensitive to the applied field rather than showing an increase of magnetization below 6 K. This behavior is consistent with the characteristics of quantum spin liquid, in which strong quantum fluctuations lead to the disorder at low temperatures. We will discuss more about the experimental details about whether a strong spin frustrated antiferromagnetic phase is formed in sodium-doped 2,2′-bipyridine and whether it enters a quantum spin liquid state at low temperatures.