Phase separation in strained cation- and anion-deficient Nd0.52Sr0.48MnO3 films

Autor: J. B. Kim, A. A. Mukhin, V. L. Svetchnikov, G. G. Levchenko, V. A. Khokhlov, V. P. Pashchenko, Yu. M. Nikolaenko, Yu. V. Medvedev, A. Yu. Prokhorov, G. Y. P. Lee, J. S. Park, V. G. Prokhorov, N. I. Solin
Rok vydání: 2011
Předmět:
Zdroj: Technical Physics. 56:1475-1486
ISSN: 1090-6525
1063-7842
DOI: 10.1134/s1063784211100100
Popis: The magnetic and transport properties of anion- and cation-deficient Nd0.52Sr0.48MnO3 films with different thicknesses, as well as of two films from this system grown on different SrTiO3 and LaAlO3 substrates, are studied. Below Curie temperature T C, the films with different thicknesses exhibit phase separation: they represent magnetic clusters (drops) embedded in a nonconducting paramagnetic (at T > T N, where T N is the Neel temperature) or antiferromagnetic (T < T N) matrix. The temperature dependences of the resistivity of the films are well described in terms of the polaron mechanism of conduction. In external magnetic field H = 0.01 T, the drops may reach 15 nm in size. They consist of magnetic polarons with a small radius (1–2 nm). The drops are shown to interact with each other in the films. Because of competition between drop-drop dipole interaction and the magnetic energy, the drops disintegrate into droplets with a size comparable to that of a magnetic polaron in a field of 1 T. An explanation is given for the discrepancy between our results and the frequently observed growth of the drops with a rise in the external magnetic field. As the film gets thicker, the fraction of the ferromagnetic phase grows with thickness nonlinearly. In the film grown on SrTiO3 (compressed by 0.9%), the characteristic Neel and Curie temperatures are lower than in the film grown on LaAlO3. The diameters of ferromagnetic drops (both maximal at H = 0.01 T and minimal at H = 1 T) turn out to be roughly the same as in the films with different thicknesses.
Databáze: OpenAIRE
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