We measured the magnetic heat capacity, susceptibility and magnetization of (CH3)4NCo(NO2)3 (TMCON) which is the iso-structural compound with the Haldane compound (CH3)4NNi(NO2)3 (TMNIN). From the analysis of these thermodynamic properties, we found that TMCON is a one-dimensional S=1/2 Ising system where the ferromagnetic nearest neighbor interaction J1 and the antiferromagnetic next-nearest neighbor interaction J2 are competing. The value of J1 is estimated to be J1/kB=28.0±4.0 K. It is confirmed that the results can be comprehensively explained only when we take J2<0, although J2=−0.22J1 estimated from the thermal analysis differs from J2=−0.46 J1 from the magnetic susceptibility for the powdered sample. Based on the results for TMCON, we discuss the stabilization of the Haldane state in TMNIN, considering the frustration effect between J1 and J2.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)