Magnetic and transport properties controlled by structural disorder in La₀.₇Ca₀.₃MnO₃ films

• Date: 2004
• Main Authors: Prokhorov, V.G., Komashko, V.A., Kaminsky, G.G., Svetchnikov, V.L., Lee, Y.P., Park, S.Y.
• Format: Article
• Language: English
• Published: Фізико-технічний інститут низьких температур ім. Б.І. Вєркіна НАН України 2004
• Series: Физика низких температур
• Subjects: Низкотемпеpатуpный магнетизм
• Online Access: https://nasplib.isofts.kiev.ua/handle/123456789/119849
• Journal Title: Digital Library of Periodicals of National Academy of Sciences of Ukraine
• Cite this: Magnetic and transport properties controlled by structural disorder in La₀.₇Ca₀.₃MnO₃ films / V.G. Prokhorov, V.A. Komashko, G.G. Kaminsky, V.L. Svetchnikov, Y.P. Lee, S.Y. Park // Физика низких температур. — 2004. — Т. 30, № 9. — С. 938–944. — Бібліогр.: 21 назв. — англ.

The magnetic properties of an amorphous, a partially-disordered, and a lattice-strained crystalline La₀.₇Ca₀.₃MnO₃ film are investigated. It is shown that the amorphous film exhibits Curie- Weiss-type paramagnetism with the effective magnetic moment of 4.2 µB/Mn ion and a small ferromagnetic contribution governed by the formation of a quasi-two-dimensional crystalline interfacial inclusions. The crystalline film with nanocrystalline randomly-oriented inclusions demonstrates a superposition of ferromagnetic (in the crystalline matrix) and superparamagnetic (in the inclusions) nature. The fitted average size of the superparamagnetic particles in the case of a Langevin function is coincident with that of the nanocrystalline clusters reveated in high-resolution electron-microscopy images. An increase in the applied magnetic field leads to a reduction in the average magnetic moment of superparamagnetic particles, which is due to an enhancement of the ferromagnetic coupling between the individual randomly-oriented crystallites. The completely crystalline film undergoes only a ferromagnetic transition with a saturation magnetization at 5 K of 2.73 µB /Mn ion.