NMR study of Ni50+xTi50-x Strain-Glass
| Autor: | Li, Rui, Santiago, Jacob, Salas, Daniel, Karaman, Ibrahim, Ross Jr, Joseph H. |
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| Rok vydání: | 2023 |
| Předmět: | |
| Zdroj: | Phys. Rev. B 107, 144207 (2023) |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1103/PhysRevB.107.144207 |
| Popis: | We studied Ni50+xTi50-x with compositions up to x = 2, performing 47Ti and 49Ti nuclear magnetic resonance (NMR) measurements from 4 K to 400 K. For large x in this system, a strain-glass appears in which frozen ferroelastic nano-domains replace the displacive martensite structural transition. Here we demonstrate that NMR can provide an extremely effective probe of the strain glass freezing process, with large changes in NMR line-shape due to the effects of random strains which become motionally narrowed at high temperatures. At the same time with high-resolution x-ray diffraction we confirm the lack of structural changes in x >= 1.2 samples, while we show that there is little change in the electronic behavior across the strain glass freezing temperature. NMR spin-lattice relaxation time (T1) measurements provide a further measure of the dynamics of the freezing process, and indicate a predominantly thermally activated behavior both above and below the strain-glass freezing temperature. We show that the strain glass results are consistent with a very small density of critically divergent domains undergoing a Vogel-Fulcher-type freezing process, coexisting with domains exhibiting faster dynamics and stronger pinning. Comment: 14 pages, 14 figures |
| Databáze: | arXiv |
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