High Magnetic Field Measurements on single crystalline (5-MAP)₂CuBr₄

(2-amino-5-methylpyridinium)₂CuBr₄, abbreviated as (5-MAP)₂CuBr₄, has been characterized as a square S=1/2 Heisenberg antiferromagnetic lattice [1,2]. The compound consists of two-dimensional sheets of highly distorted CuBr₄ tetrahedra separated by the organic cations. The magnetic coupling constants are 6.5 K for the intra-sheet coupling, 1.5 K for a residual inter-sheet coupling, with both interactions in effect resulting in an antiferromagnetic transition occurring at T_N = 3.8 K. Here we report a single crystal high magnetic field study on (5-MAP)₂CuBr₄, with magnetic fields up to 40 T at temperatures down to 1.5 K. From the data additional information on local anisotropies such as of the g-factor can be obtained and will be discussed.