Synthesis Condition Dependence of
Magnetic Property of
Ni(OH)2 Monolayer Nanocluster
Synthesized from Sodium Orthosilicate

Heat capacities and magnetic susceptibilities of Ni(OH)2 monolayer nanoclusters (Ni-MNC) in amorphous SiO2 synthesized with various concentration ratios of NiCl2 and Na4SiO4 solutions were measured. The Ni-MNCs exhibited a broad heat capacity anomaly around 20 K. Magnetic entropies for the Ni-MNCs were smaller than the expected value for S = 1 spin systems (Rln3 = 9.13 J K−1 mol−1), which suggests that the Ni-MNCs show a spin-glass-like behavior. Magnetic susceptibility measurements indicated that the blocking temperature of the Ni-MNC by Na4SiO4 is higher than that by Na2SiO3, which would be attributed to a dipole-dipole interaction between the Ni-MNCs.

(by T. Maruoka & Y. Miyazaki)

Fig. 1. Magnetic heat capacities of Ni-MNCs in the samples A, B, and C.

Fig. 2. Magnetic susceptibilities of Ni-MNCs synthesized from Na4SiO4 and Na2SiO3. Blocking temperatures are indicated by arrows.