Magnetic Critical‐Point Behavior of CrO2
| Autor: | J. S. Kouvel, D. S. Rodbell |
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| Rok vydání: | 1967 |
| Předmět: | |
| Zdroj: | Journal of Applied Physics. 38:979-981 |
| ISSN: | 1089-7550 0021-8979 |
| DOI: | 10.1063/1.1709710 |
| Popis: | The magnetization σ of the ferromagnetic compound CrO2 was measured as a function of field H and temperature T near the Curie point Tc. From isotherms of σ2 vs H/σ, the initial susceptibility χ0 above Tc was obtained, which when tested against the relationship χ0−1 ∝ (T−Tc)γ gives a constant γ of 1.63±0.02 from just above Tc (386.5°K) up to about 1.15 Tc. This γ value contrasts with the values near43 recently computed for the Heisenberg model and later found experimentally in various ferromagnetic metals and compounds. At higher temperatures the effective γ decreases rapidly towards unity. Up to the highest field used (25 kOe), the critical isotherm obeys the relationship σ∝H1/δ with δ=5.75±0.05, which differs markedly from the theoretical δ values of 3 (molecular field) and 5.2 (3‐dimensional Ising) and from various experimental values. Gradual departure from this relationship below 1.5 kOe is attributed to the magnetocrystalline anisotropy that persists at Tc. Furthermore, we find that all the σ(H, T) d... |
| Databáze: | OpenAIRE |
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