title: The influence of low temperature on gamma-ray irradiated permanent magnets.
abstract: The temperature effect on the magnetic property of gamma-ray irradiated Nd-Fe-B and Sr-Ferrite magnets has been investigated. When the permanent magnets are exposed to gamma-ray, it's magnetic and other related properties are declined with degree of dose. The decreased magnetic property by gamma-ray irradiation at low temperature is similar with the result of magnet at high temperature. The temperature effect on the gamma-ray irradiation at exposed moment is also regarded as one of the important parameters for the reduced magnetic properties. The gamma-irradiation at low temperature was carried out at 195 K, and the changed properties of two kinds of magnets before and after gamma-irradiation were comparatively studied. The increased demagnetization of the magnets were studied by Hall probe. And changed Curie temperature and micro-crystal structure of each permanent magnet by gamma-ray irradiation has been also studied. Moreover the strong and broad single line shape of ESR signal in the resonance magnetic field is attributed to unpaired electron of Fe2+ in the sample by the effect of gamma-ray irradiation.
authors.affiliation: Department of Chemistry, Pukyong National University, Busan 608-737, Korea.
authors.forename: Young Chul
authors.initials: YC
authors.lastname: Han
authors.forename: Hyun Gil
authors.initials: HG
authors.lastname: Cha
authors.forename: Chang Woo
authors.initials: CW
authors.lastname: Kim
authors.forename: Eun Sun
authors.initials: ES
authors.lastname: Ji
authors.forename: Young Hwan
authors.initials: YH
authors.lastname: Kim
authors.forename: Dong In
authors.initials: DI
authors.lastname: Kang
authors.forename: Young Soo
authors.initials: YS
authors.lastname: Kang