Pressure-enhanced ferromagnetism and metallicity in La1.24Sr1.76Mn2O7 bilayered manganite system

• Tipo: Artigo em Revista Científica Internacional
• Data: 2013

Autores

kumaresavanji, m. (Autor) Outra; saitovitch, e. m. b. (Autor) Outra; araujo, j. p. (Autor) FCUP; fontes, m. b. (Autor) Outra

Revista

Título: Journal of Materials Science

Vol. 48

Páginas: 1324-1329

ISSN: 0022-2461

Editora: Springer Nature

Indexação

ISI Web of Knowledge - 4 Citações

Scopus - 4 Citações

Outras Informações

ID Authenticus: P-002-12P

DOI: 10.1007/s10853-012-6877-1

Abstract (EN): We report the low temperature magnetization, electrical resistance, and magnetoresistance of La1.24Sr1.76Mn2O7 bilayer manganite system under hydrostatic pressure. At ambient pressure, the compound shows a sharp ferromagnetic transition (T-C) accompanied by a metal-insulator transition (T-MI) at 130 K. We observe that the T-C and T-MI increase with hydrostatic pressure at a rate of dT(C)/dP = 2.08 K/kbar and dT(MI)/dP = 2 K/kbar, respectively. Also, we observe an appreciable increase of magnetic moments at low temperatures with increasing pressure. The high temperature regime of temperature dependence of resistivity curves was fitted with the Emin-Holstein's polaron hopping model and the calculated activation energy values suggest that the applied pressure weakens the formation of Jahn-Teller polarons. The magnetoresistance ratio (MRR) was measured at T-C and at 4.2 K upon an external magnetic field of 5 T. The observed MRR at T-C is about 210 % and the applied pressure increases the MRR significantly. These results can be interpreted by the pressure-enhanced overlap between the orbitals of Mn-O-Mn, which facilitates the charge transfer and hence enhances the ferromagnetism and metallicity.

Idioma: Inglês

Tipo (Avaliação Docente): Científica

Nº de páginas: 6