Localization of Spin Triplets in Tl_<1-x>K_xCuCl_3(Condensed Matter : Electronic Structure, Electrical, Magnetic and Optical Properties)

概要

論文の詳細を見る
The effect of exchange randomness on field-induced magnetic ordering was investigated through specific heat measurements in Tl_<1-x>K_xCuCl_3 with x ≤ 0.22. The isostructural parent compounds TlCuCl_3 and KCuCl_3 are coupled spin dimer systems with a gapped ground state and their field-induced antiferromagnetic ordering is described by the Bose-Einstein condensation (EEC) of spin triplets. Well-defined field-induced phase transitions were observed in Tl_<1-x>K_xCuCl_3. The critical exponent φ of the phase boundary defined by T(H) α (H - H_C)^<1/φ> is reevaluated in TlCuCl_3 as φ = 1.67 ± 0.07, which is close to 0BEC = 3/2 derived from the magnon EEC theory. For ≠ 0, the exponent φ decreases systematically with x. The phase boundary observed below 2K for x > 0.1 approximates a linear function of temperature T. In the low-field region for H < H_c, no magnetic ordering is observed despite finite susceptibility. These properties are discussed in connection with the Bose glass phase argued by Fisher et al.
社団法人日本物理学会の論文
2004-10-15