Spin dynamics of the square lattice Heisenberg antiferromagnet, Ba 2 MnGe2 O7, is studied by a combination of bulk measurements, neutron diffraction, and inelastic neutron-scattering techniques. Easy plane type antiferromagnetic order is identified at T≤4.0K. The exchange interactions are estimated as J1 =27.8 (3)μeV and J 2 =1.0 (1) μeV, and the saturation field HC is 9.75 T. Magnetic excitation measurements with high experimental resolution setup by triple axis neutron spectrometer reveals the instability of one magnon excitation in the field range of 0.7 HC 7Hc≤H≤0.85HC.
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|Publication status||Published - 2010 Mar 2|