• Search Research Projects
  • Search Researchers
  • How to Use
  1. Back to previous page

Development of a new method producing very low temperatures with manganese-zeolite

Research Project

Project/Area Number 63550004
Research Category

Grant-in-Aid for General Scientific Research (C)

Allocation TypeSingle-year Grants
Research Field Applied materials
Research InstitutionUniversity of Tsukuba

Principal Investigator

NARAHARA Yoshimasa  Inst. of Phys., Univ. of Tsukuba Professor, 物理学系, 教授 (40015508)

Co-Investigator(Kenkyū-buntansha) TOMINAGA Akira  Inst. of Phys., Univ. of Tsukuba Assistant Professor, 物理学系, 講師 (10015563)
Project Period (FY) 1988 – 1989
Project Status Completed (Fiscal Year 1989)
Budget Amount *help
¥2,300,000 (Direct Cost: ¥2,300,000)
Fiscal Year 1989: ¥200,000 (Direct Cost: ¥200,000)
Fiscal Year 1988: ¥2,100,000 (Direct Cost: ¥2,100,000)
KeywordsMn-zeolite / Curie-Weiss law / phase transition / relaxation mechanism / long-range correlation / dipolar interaction / magnetic ordering / adiabatic demagnetization / ゼオライト / 磁化率 / 常磁性 / 反強磁性 / ESR
Research Abstract

Our sample, Mn-zeolite was fabricated substituting some of sodium ions for manganese ions in zeolite-Y, Na_<50> (AlO_2)_<50> (SiO_2)_<142> 25OH_2O (the product of Tosoh Co.). Concentration of Mn^<2+> was measured by chemical analysis, ICP-OES and X-ray microanalysis. Most Mn^<2+> were found to exist in supercages from the results of X-ray diffraction and EXAFS and likely to distribute fairly uniformly in the samples. Mn^<2+> concentrations and average distances between ions of our two samples are 10^<-3> mol/g, 9.4 A and 10^<-4> mol/g, 20 A respectively.
Temperature dependence of susceptibility was measured from 300 K to 20 mK. Curie-Weiss law is satisfied from 300 K to 50 mK in our sample of higher concentration (Curie constant: 4.0 x 10^<-3> emu/g; Weiss temperature: -50 mK). The effective magnetic moment of Mn^<2+> is 5.58 mu_B close to that of free Mn ions. Susceptibility has maximum around 30 mK which shows that phase transition takes place. Temperature and frequency dependence of … More the susceptibility below 1 K shows that relaxation mechanism is governed not by a single relaxation time, but distributed relaxation times. Especially Cole equation with consideration of long-range correlation between spins explains results below 40 mK.
ESR experiment was performed from 300 K to 40 mK. g value is 2 and line width is also independent of temperature. Interaction between ions is mainly dipolar interaction. The line width in X-band is 650 gauss which is interpreted as the sum of 220 gauss of dipolar and 430 gauss of hyperfine interaction. Magnetic ordering at low temperatures is mainly due to this dipolar interaction.
Performing adiabatic demagnetization with initial conditions of 1.3 K and 5 T, we obtained about 80 mK. The lattice temperature of Mn-zeolite follows well the spin temperature down to this temperature. Internal field of this sample is considered to be small since the temperature produced is nearly proportional to the external field down to the minimum temperature. Less

Report

(3 results)
  • 1989 Annual Research Report   Final Research Report Summary
  • 1988 Annual Research Report
  • Research Products

    (6 results)

All Other

All Publications (6 results)

  • [Publications] Satoru Okayasu: "DC-SUSCEPTIBILITY OF Mn-ZEOLITE Y" Solid State Communications. 73. 593-596 (1990)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1989 Final Research Report Summary
  • [Publications] Satoru Okayasu: "Magnetic Properties of Mn-Zeolite-Y" Journal of Physical Society of Japan.

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1989 Final Research Report Summary
  • [Publications] Satoru Okayasu, Kyoko Miyabe, Ken-ichi Chahara, Akira Tominaga, Yoshimasa Narahara: "DC-SUSCEPTIBILITY OF Mn-ZEOLITE Y" Solid State Communication, 73, No.9, 593-596, 1990.

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1989 Final Research Report Summary
  • [Publications] Satoru Okayasu, Kyoko Miyabe, Ken-ichi Chahara, Akira Tominaga, Yoshimasa Narahara: "Magnetic Properties of Mn-Zeolite-Y" Journal of Physical Society of Japan.

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1989 Final Research Report Summary
  • [Publications] Satoru Okayasu: "DC-SUSCEPTIBILITY OF Mn-ZEOLITE Y" Solid State Communications. 73. 593-596 (1990)

    • Related Report
      1989 Annual Research Report
  • [Publications] Satoru Okayasu: "Magnetic Properties of Mn-Zeolite-Y" Journal of Physical Society of Japan.

    • Related Report
      1989 Annual Research Report

URL: 

Published: 1988-04-01   Modified: 2016-04-21  

Information User Guide FAQ News Terms of Use Attribution of KAKENHI

Powered by NII kakenhi