Relaxation Kinetics of the Microhardness of KDP Crystals after Their Exposure to a Magnetic Field
| Autor: | Igor M. Pritula, Alexey E. Voloshin, V. I. Alshits, M. V. Koldaeva, E. V. Darinskaya |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
010302 applied physics
Materials science Physics and Astronomy (miscellaneous) Solid-state physics Potassium Analytical chemistry chemistry.chemical_element 02 engineering and technology 021001 nanoscience & nanotechnology 01 natural sciences Indentation hardness Magnetic field Crystal Amplitude chemistry 0103 physical sciences Hardening (metallurgy) 0210 nano-technology Softening |
| Zdroj: | JETP Letters. 108:231-236 |
| ISSN: | 1090-6487 0021-3640 |
| Popis: | It has been shown that potassium dihydrogen phosphate crystals change their microhardness reversibly after their exposure to a magnetic field of B = 0.8 or 1.2 T for tm = 7–90 min. It has been found that the magnetic effect can be conveniently characterized by the quantity B2tm, because the variation of the parameters conserving B2tm=const does not change the result. At B2tm < 10 T2 min, the effect is almost absent. Above this threshold, the amplitude of changes in the microhardness increases and approaches a constant value of ~10% at B2tm ≈ 19 T2 min. The responses of samples of the same crystal from the faces of the prismatic and pyramidal growth sectors to exposure are different. In the former case, they soften; in the latter case, the hardening stage follows the softening stage. However, in both cases, the microhardness returns to the initial value. At B2tm values from 19 to 37 T2 min, the amplitudes and durations of the effect do not change, but in the narrow range of 37–43 T2 min, the lifetime of the modified state increases sharply with transition to a new level: “sharp” peaks with a half-width of ~2 days are transformed to trapezoids with the width of the horizontal side of ~1–2 weeks. A physical scheme of the observed effects has been proposed. |
| Databáze: | OpenAIRE |
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