Crossover between the second- and first-order magnetic transition in ferromagnetic manganites
| Autor: | A. N. Ulyanov, Miroslav Maryško, Pavel Novák, M. M. Savosta |
|---|---|
| Rok vydání: | 1999 |
| Předmět: |
Physics
Condensed Matter::Materials Science Phase transition Paramagnetism Magnetization Magnetic anisotropy Mean field theory Magnetic moment Ferromagnetism Condensed matter physics Condensed Matter::Strongly Correlated Electrons Astrophysics::Cosmology and Extragalactic Astrophysics Magnetic susceptibility |
| Zdroj: | Physical Review B. 60:6655-6661 |
| ISSN: | 1095-3795 0163-1829 |
| Popis: | The temperature dependence of the magnetic moment in ${\mathrm{La}}_{0.7}{\mathrm{Sr}}_{0.3}{\mathrm{MnO}}_{3}$ and ${\mathrm{La}}_{0.7}{\mathrm{Ca}}_{0.3}{\mathrm{MnO}}_{3}$ ferromagnetic manganites was studied by means of dc magnetic measurements and by NMR on ${}^{55}\mathrm{Mn}$ nuclei. In addition, for temperatures close to ${T}_{C},$ the ac susceptibility and the NMR spin-lattice relaxation were determined. From the results it follows that the phase transition changes from the conventional continuous second order for ${\mathrm{La}}_{0.7}{\mathrm{Sr}}_{0.3}{\mathrm{MnO}}_{3}{(T}_{C}=364$ K) to more abrupt but close to continuous for ${\mathrm{La}}_{0.7}{\mathrm{Ca}}_{0.3}{\mathrm{MnO}}_{3}{(T}_{C}$=265 K). The change of the character of the phase transition is explained on the basis of the mean field theory of double exchange taking into account the spontaneous magnetostriction. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|