IRRADIATION OF MAGNETIC MATERIALS WITH 1.5- AND 4-Mev PROTONS
Pure iron and 5% molybdenum Permalloy samples, 0.01 in. thick, were irradiated with 1.5 and 4-Mev protons at total incident integrated fluxes of 10/ sup 16/ and 10/sup 17/ protons per cm/sup 2/. The actual shapes used were a ring 13/16-in o.d. x 5/8 in. i.d. and a disk of 5/8-in. diameter. The ring was utilized for d-c magnetic property measurements (before and after irradiation) while the disk was used for magnetic anisotropy torque measurements. The remanence (Br) and maximum permeabiiity ( mu --) of molybdenum Permalloy decreised by about 35%. This is of the same order of change produced by neutron irradiation of 10/sup 17/ n/cm/sup 2/ in this material. However, measurements to date indicate that changes in coercive force and initial permeability due to proton irradiation are relatively small as compared with neutron irradiation effects. The decreases in B/sub r/ and mu /sub m/of the pure iron samples were of the order of l0 to 20% for irradiations of both approximates 10/sup 16/ and approximates 10/sup 17/ protons/cm/sup 2/. Both materials were essentially isotropic initially. Post irradiation torque measurements showed that the materials became slightly more isotropic. No changes were observed in saturation magnetization. Heating of control samples to 250 deg C did not produce changes in magnetic properties, showing that temperature aione is not a factor in producing the permanent changes that occurred under irradiation. All irradiations were performed at temperatures below 250 deg C. The changes due to proton irradiation are thought to be due to protoninduced disordering. (auth)
- Research Organization:
- Naval Ordnance Lab., Silver Spring, Md.
- NSA Number:
- NSA-17-037701
- OSTI ID:
- 4630251
- Journal Information:
- Journal of Applied Physics (U.S.), Vol. Vol: 34; Other Information: Orig. Receipt Date: 31-DEC-63
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
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