1986 Fiscal Year Final Research Report Summary
Magnetic Properties for the Metallic Superfine Particles Formed in X Zeolites
| Project/Area Number |
60540218
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
物性一般（含極低温･固体物性に対する理論）
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| Research Institution | Hokkaido University of Education |
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Principal Investigator |
TAKAYANAGI Sigeru Physics Division,Sapporo Campus,Hokkaido University of Education, 教育学部, 助教授 (50013529)
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| Co-Investigator(Kenkyū-buntansha) |
WADA Nobuo Department of Physics,Faculty of Science,Hokkaido University, 理学部, 助手 (90142687)
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| Project Period (FY) |
1986
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| Keywords | Zeolite / Superfine Particle / Susceptibility / Magnetic Anisotropy / SQUID / 析出 / 超常磁性 |
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| Research Abstract |
A.C. magnetic susceptibility measurements have been performed on the superfine Ni metallic particles prepared inside the cavities of X zeolites. The measurements were carried out in the temperature range 4.2-300 K by using a Hokusan SQUID magnetometer, model HS-1R on the samples,A,B,and C which have different particle diameters. The magnetic susceptibilities of the sample A increases with decreasing temperature from room temperature down to 50 K, and then decreases rapidly. The temperature dependence and the value of Curie constant may be described within the Neel model of superparamagnetism. But the blocking temperature <T_f> of these systems is inversely proportional to the particle size. So our experimental results on Ni fine particles in X zeolite differ from other one. In order to understand the observations, an attempt has been made to caluculate the temperature dependence of the magnetic susceptibility using a Hamiltonian of the form H=-2 <mu_B> N. <S_z> ・H-D・ <S_z2> where N is number of atoms per particle, S is spin quantum number,and H is the external magnetic field. It is found that the calculation has been successful to explain the temperature dependence of the A.C. magnetic susceptibilities for Ni superfine particle systems with the fitting parameter D = 75, 330, and 470 K coresponding to the sample,A,B,and C respectively. In coclusion, we have observed new superparamagnetism for the superfine Ni particles formed in X zeolites.
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