Determination of the Exchange Integrals in β-MnO_2

概要

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Magnetic susceptibility and specific heat of the β-MnO_2 powder specimen have been measured in the range 20 to 300°K and 77 to 100°K respectively. The measurements have also been made for the paramagnetic inelastic neutron scattering at room temperature by using time-of-flight method. The values of the Weiss temperature, of the Neel temperature and of the average full width at half maximum of the neutron energy distribution (Gaussian) have been determined as 1050°K, 92°K and 13 meV respectively. The exchange integrals (J_n) are determined by combining these experimental data with the theoretical relations between exchange interactions and physical properties and by assuming J_1/J_2=1.60: J_1=8.9 (antiferromagnetic), J_2=5.5 and J_3=-1.3°K, where J_1 is the exchange integral between nearest neighbours (in the <001> direction), J_2 acts between next nearest neighbours (<111> direction) and J_3 refers to third-neighbour coupling.
社団法人日本物理学会の論文
1971-05-05