µSR Study on Antiferromagnetism of Alkali-Metal Clusters Incorporated in Zeolite Sodalite

Neutron Diffraction Study of Antiferromagnetic Potassium Nanoclusters Incorporated into Sodalite

“…We confirmed that the temperature dependence of the magnetic susceptibility in the present sample shows a peak at approximatery 70 K corresponding to T N . This is in good agreement with that in reported works [10,11,13]. For the ND experiments, a powder of 3.6 grams was put in a vanadium-film cylinder, 18-mm diameter, and sealed in an aluminum can filled with helium gas.…”

“…According to the Curie-Weiss law observed in the magnetic susceptibility above T N , each β cage accommodates one unpaired spin of s = 1/2 [11]. The situation does not change even if we substitute K atoms for Na ones.…”

“…Under a magnetically ordered state at low temperatures, it is generally expected that the spin fluctuation is less in three dimensional systems. Moreover, it was found by muon spin rotation (µSR) experiments that the internal magnetic field of K/K 3 -SOD is obviously higher than that in Na/Na 3 -SOD at low temperatures [11]. Therefore, the reduction in µ is hardly expected.…”

“…We prepared K 3+ 4 clusters in sodalite by adopting the method described in the previous work [11]. The sample is a powder specimen with the crystal size of a few micrometer.…”

“…Other alkali cations can be substituted for the Na + ions. A systematic increase in T N has been found, i. e., T N 72 K in K 3+ 4 clusters, 80 and 100 K in K-Rb alloy clusters of (K 3 Rb) 3+ and (K 1.5 Rb 2.5 ) 3+ , respectively [9][10][11][12][13][14]. These materials are assigned to Mott-Hubbard insulators under a just-half-filled condition of s-like band formed by the three dimensional array of clusters [15][16][17].…”