Initial susceptibility study of a magnetic transition in the two dimensional system (CH3NH3)2MnCl4. Absorption and dispersion in the neighborhood of the critical temperature

Magnetic susceptibility measurements on the layer structured system bis(methylammonium) tetrachloromanganate(II) revealed a transition centered at 45.3°K, and a broad maximum in the susceptibility at 80°K. The critical exponents for the sharp transition were found to be γ′ =2.39(7), T < Tc, and γ=2.90(13), T > Tc. The susceptibility was found to be field dependent below Tc, with (∂χ/∂H)T > 0.