Study of γ-ray irradiation effect on permanent magnets

Abstract

Irradiation damage of FeCrCo, AlNiCo, SmCo, and NdFeB permanent magnets was investigated by using γ-ray irradiation. Results of magnetic property measurement show that FeCrCo and NdFeB have more demagnetization than AlNiCo and SmCo. X-ray diffraction analysis shows that γ-ray irradiation leads to the increase of FeCrCo crystal mismatch and decrease of AlNiCo ordering degree. The investigations by positron annihilation spectroscopy technique show that the defects in AlNiCo and SmCo increase after γ-ray irradiation. The defects induced by γ-ray irradiation in NdFeB magnets are not the main source that leads to partial demagnetization. The irradiation resistances of these magnets are discussed in detail considering the thermal stability, coercivity mechanisms, and defect damage.

Effects of gamma-Ray Radiation on Magnetic Properties of NdFeB and SmCo Permanent Magnets for Space Applications

“…Previous investigations on the effects of gamma and neutron radiation on Neodymium or Cobalt based permanent magnets typically demonstrate deterioration of magnetic properties [5] and changes in crystal structure [6]. In contrast, results achieved during this test show that the magnetic moment tends to increase after irradiation in 88% of the samples and decreases in the rest.…”

“…Radiationinduce thermal effects on creation and diffusion of defects may play a role on the observed changes on the magnetization, due to the volume changes and magnetostriction effects, and magnetic properties of the defects. However, previous studies suggest that defect formation induced by y-ray irradiation is very small [6].…”

Monte Carlo study of radiation-induced demagnetization using the two-dimensional Ising model

“…This phenomenon has been observed experimentally in different forms. For example, gamma rays are less likely to cause radiation damage than neutrons or protons [16,[26][27][28][29][30]. One of the main reasons for this observed difference is the fact that gamma rays typically interact with the electrons, which then transfer their energy to the lattice through electron-phonon interactions, whereas neutrons directly interact with the nuclei of atoms and deposit their energy directly onto the crystal structure.…”

An energy supply unit for an autonomous remote sensor system monitoring stored nuclear waste

“…The prototype comprises three permanent rare earth Neodymium Iron Boron (NdFeB) magnets arranged longitudinally along a carbon fibre shaft. More radiation resistant magnets can be used such as Samarium Cobalt (SmCo) as indicated in several studies [42][43][44][45][46].…”