Abstract
The effect of low x-ray irradiation doses (≈102 rad) on the magnetoplastic effect — the detachment of dislocations from paramagnetic centers under the action of an external magnetic field B — in alkali-halide crystals has been investigated. The measurements were performed on LiF crystals and three types of NaCl crystals, differing in impurity content. The dependence of the mean free path l of the dislocations on the rotational frequency ν of a sample in a magnetic field was especially sensitive to low irradiation doses. In unirradiated crystals this dependence is a single-step dependence and is characterized by a critical frequency ν c ∝B 2 above which the magnetoplastic effect is not observed. The frequency ν c depends only on the type of paramagnetic centers, and not on their density. Even the lowest irradiation dose employed (<100 rad) leads to a sharp restructuring of the dependence l(ν), converting it into a two-step dependence (for edge dislocations) with an additional critical frequency ν c2, that is insensitive to the irradiation dose, and that corresponds to the appearance of magnetically sensitive stoppers of a new type under irradiation. The initial critical frequency ν c1, as a rule, also varies with the dose, reflecting the change in state of the impurity complexes (Ca in NaCl and Mg in LiF). Specifically, it is shown for NaCl(Ca) crystals that as the irradiation dose increases, the frequency ν c1 increases, gradually approaching the value ν c2, so that by the time the dose is ≈300 rad, the dependence l(ν) once again becomes a single-step dependence, dropping sharply only for ν⩾ν c2. It is shown that the addition of a small number of Ni atoms to a NaCl crystal makes the Ca complexes radiation resistant, and the critical frequency ν c1 corresponding to them initially equals ν c2 for crystals with no Ni. The recombination kinetics of radiation defects in the case in which the samples are irradiated under a tungsten lamp was investigated. A possible physical model of the observed dependences is discussed.
Similar content being viewed by others
References
N. Itoh, Adv. Phys. 31, 491 (1982).
Ch. B. Lushik and A. Ch. Lushik, Decay of Electronic Excitations with Formation of Defects in Solids [in Russian], Nauka, Moscow (1989), p. 263.
V. I. Al’shits, E. V. Darinskaya, and O. L. Kazakova, JETP Lett. 62, 375 (1995).
V. I. Al’shits, E. V. Darinskaya, T. M. Perekalina, and A. A. Urusovskaya, Fiz. Tverd. Tela (Leningrad) 29, 467 (1987) [Sov. Phys. Solid State 29, 265 (1987)].
V. I. Al’shits, E. V. Darinskaya, and E. A. Petrzhik, Fiz. Tverd. Tela (Leningrad) 33, 3001 (1990) [Sov. Phys. Solid State 33, 1694 (1990)].
V. I. Al’shits, R. Voska, E. V. Darinskaya, and E. A. Petrzhik, Fiz. Tverd. Tela (St. Petersburg) 35, 70 (1993) [Phys. Solid State 35, 37 (1993)].
V. I. Al’shits, E. V. Darinskaya, and E. A. Petrzhik, Fiz. Tverd. Tela (St. Petersburg) 35, 320 (1993) [Phys. Solid State 35, 162 (1993)].
V. I. Al’shits, E. V. Darinskaya, and E. A. Petrzhik, Mat. Sci. Eng. A 164, 322 (1993).
V. I. Al’shits, E. V. Darinskaya, O. L. Kazakova et al., Izv. Ross. Akad. Nauk, Ser. Fiz. 57, 2 (1993).
V. I. Al’shits, E. V. Darinskaya, O. L. Kazakova et al., J. Alloys and Compounds 211/212, 548 (1994).
V. I. Al’shits, E. V. Darinskaya, O. L. Kazakova et al., JETP Lett. 63, 668 (1996).
Yu. I. Golovin and R. B. Morgunov, JETP Lett. 58, 191 (1993).
Yu. I. Golovin and R. B. Morgunov, Fiz. Tverd. Tela (St. Petersburg) 35, 2581 (1993) [Phys. Solid State 35, 1280 (1993)].
Yu. I. Golovin and R. B. Morgunov, Fiz. Tverd. Tela (St. Petersburg) 37, 1239, 1352, 2118 (1995) [Phys. Solid State 37, 674, 734, 1152 (1995)].
Yu. I. Golovin and R. B. Morgunov, JETP Lett. 61, 596 (1995).
Yu. I. Golovin, R. B. Morgunov, and A. V. Turunnik, Phys. Status Solidi B 189, 1 (1995).
M. I. Molotskii, Fiz. Tverd. Tela (Leningrad) 33, 3112 (1991) [Sov. Phys. Solid State 33, 1760 (1991)].
M. I. Molotskii, Fiz. Tverd. Tela (St. Petersburg) 35, 11 (1993) [Phys. Solid State 35, 5 (1993)].
M. I. Molotskii, R. E. Kris, and V. Flerov, Phys. Rev. B 151, 12531 (1995).
Ya. B. Zel’dovich, A. L. Buchachenko, and E. L. Frankevich, Usp. Fiz. Nauk 155, 3 (1988) [Sov. Phys. Usp. 31, 385 (1988)].
A. L. Buchachenko, R. Z. Sagdeev, and K. Z. Sadikov, Magnetic Spin Effects in Chemical Reactions [in Russian], Nauka, Novosibirsk (1978), p. 296.
L. F. Mollenauer, S. Pan, and J. Winnacker, Phys. Rev. Lett. 26, 1643 (1971).
V. B. Pariiskii, A. I. Landau, and V. I. Startsev, Fiz. Tverd. Tela (Leningrad) 5, 1377 (1963) [Sov. Phys. Solid State 5, 1002 (1963)].
S. Radhakrishna and B. V. R. Crowdari, Phys. Status Solidi A 14, 11 (1972).
J. H. Crawford and C. M. Nelson, Phys. Rev. Lett. 5, 314 (1960).
W. Haeys, J. Appl. Phys. 33, 329 (1962).
W. Haeys and J. Wilkens, Proc. Roy. Soc. A 281, 340 (1964).
M. L. Kats and V. Z. Semenov, Opt. Spektrosk. 4, 637 (1958).
I. A. Parfianovich, Opt. Spektrosk. 6, 189 (1959).
M. L. Kats, Luminescence and Electron-Hole Processes in Photochemical Crystals of Alkali-Halide Compounds [in Russian], Saratov University Press, Saratov (1960), p. 109.
Author information
Authors and Affiliations
Additional information
Zh. Éksp. Teor. Fiz. 111, 615–626 (February 1997)
Rights and permissions
About this article
Cite this article
Al’shitz, V.I., Darinskaya, E.V. & Kazakova, O.L. Magnetoplastic effect in irradiated NaCl and LiF crystals. J. Exp. Theor. Phys. 84, 338–344 (1997). https://doi.org/10.1134/1.558122
Received:
Issue Date:
DOI: https://doi.org/10.1134/1.558122