Effects of spin-phonon interaction on transport, magnetic properties and the oxygen isotope effect in R1−xAxMnO3 |
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| Authors: | Yuanjie HuangLi Pi Yuheng Zhang |
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| Affiliation: | a High Magnetic Field Laboratory, Chinese Academy of Sciences and University of Science and Technology of China, Hefei 230026, People''s Republic of China
b Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026, People''s Republic of China |
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| Abstract: | We consider the spin-phonon (s-p) coupling as an important correction to the double exchange and the dynamic Jahn-Teller effect in colossal magnetoresistance systems R1−xAxMnO3. The effect of s-p on transport, magnetic properties and the oxygen isotope effect has been studied by utilizing the perturbation theory and mean field theory. It is indicated that (i) a formula for the shift of the ferromagnetic (FM) transition temperature Tc is given, from which it could be seen that the s-p coupling could yield an excitation gap for long-wavelength acoustic spin waves and an applied field could improve Tc, (ii) the relation Tc∼m−1/2 (m is the mass of the anion) is obtained, which suggests that the oxygen isotope effect is dominated by both the s-p and e-p interaction, (iii) it could cause the hardening of phonon frequency in the FM state, (iv) s-p could lead to the increase of the resistivity which is proportional to T3 at low temperature and proportional to T at high temperature in the ferromagnetic metallic region of R1−xAxMnO3. |
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| Keywords: | Spin-phonon coupling Isotope effect Magnetism |
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