Lambda (λ) Transition in the Heat Capacity by Finite Block Spin Phenomenology
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We explain the lambda (λ) transition in the heat capacity in terms of spin freezing on the basis of finite-sized block spin concepts. Thus, the spin-glass phase or the antiferromagnetic/paramagnetic phase near the Néel temperature may be considered as a short-range ordering of the block spins comprised of many random spins with respective majority spin directions. Using the Curie law for the block spins, we obtain the λ-type heat capacity in the lower and the higher temperature approximations of the Brillouin function. The theoretical heat capacity gives a good fit to the experimental data.
KeywordsHeat capacity N´eel temperature Lambda (λ) transition Antiferromagnetic phase transition
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This work was supported by the National Research Foundation of Korea (Project Nos. 2016R1D1A1A0991 7003 and 2019R1A2C1002076).
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