Shoichi Nagata

Susceptibility and Specific Heat for Cu(NH3)2·Ni(CN)4·2C6H6

The magnetic susceptibility and the specific heat of Cu(NH 3 ) 2 ·Ni(CN) 4 ·2C 6 H 6 in powder specimen has been measured between 0.2 and 20.4 K. Broad maximums are observed near 3 K in both experimental results, but the information for phase transition to the long range order can not be obtained down to 0.2 K. These results give the behaviour of low dimensional magnetic lattice for this crystal. The susceptibility data is explained as the one dimensional antiferromagnetic spin system with exchange interaction | J |=2.31 K.

Antiferromagnetic Ordering in Mn(NH3)2·Ni(CN)4·2C6H6

The magnetic susceptibility and the specific heat of Mn(NH 3 ) 2 ·Ni(CN) 4 ·2C 6 H 6 for powder specimen have been measured from 0.3 K to 20 K. The Neel temperature is found at 0.66 K. The Weiss temperature is obtained as –1.52 K with antiferromagnetic coupling. The relation between susceptibility and specific heat which is known as the Fishers relation is experimentally verified. The broad maximum of specific heat is observed near 3 K. The origin is not explained as magnetic system through the entropy analysis.

ESR of Cu2+ in Cd(NH3)2·Ni(CN)4·2C6H6

ESR for isolated Cu 2+ ions and exchange-coupled pairs of Cu 2+ ions in diamagnetic single crystal of Cd(NH 3 ) 2 ·Ni(CN) 4 ·2C 6 H 6 have been studied. As for the isolated ions, the spin Hamiltonian parameters, g , A and the transferred hyperfine constant due to the neighbouring nitrogen ions are determined. As for the Cu 2+ pairs, the ground state is concluded to be antiferromagnetic with the exchange parameter J of (7±1) K from the temperature dependence of their intensity.

Low-Dimensional Magnetic Behavior of Cu(NH3)2 · Ni (CN)4 · 2C6H6

The crystal symmetry of Cu(NH3)2 · Ni(CN)4 · 2C6H6 is tetragonal and the space group is P 4/m, as shown in Fig. 1.1,2 The magnetic susceptibility was measured by the ac Hartshon bridge method at 80 Hz. The temperature range for the present experimental measurement is between 0.2 and 20.4°K. The temperature range in the specific heat measurement is between 1.2 and 20.4°K.3,4