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

• Type: Article in International Scientific Journal
• Date: 2013

Authors

kumaresavanji, m. (Author) Other; saitovitch, e. m. b. (Author) Other; araujo, j. p. (Author) FCUP; fontes, m. b. (Author) Other

Journal

Title: Journal of Materials Science

Vol. 48

Pages: 1324-1329

ISSN: 0022-2461

Publisher: Springer Nature

Indexing

ISI Web of Knowledge - 4 Citations

Scopus - 4 Citations

Other information

Authenticus ID: 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.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 6