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Variations in the electrical resistivity of La0.67Ca0.33MnO3 films and induced interconversions of ferromagnetic and nonferromagnetic inclusions in their bulk

Y.A. Boikov ; Tomas Liljenfors ; Eva Olsson (Institutionen för teknisk fysik, Mikroskopi och mikroanalys) ; Tord Claeson (Institutionen för mikroteknologi och nanovetenskap, Kvantkomponentfysik) ; V.A. Danilov
Physics of the Solid State (1063-7834). Vol. 53 (2011), 10, p. 2168-2173.
[Artikel, refereegranskad vetenskaplig]

A significant (similar to 1.8%) positive unit between the parameters of the crystal lattice is the reason of tetragonal distortion (a (aSyen)/a (aEuro-) a parts per thousand 1.04) and reduction in the volume of the unit cell of La(0.67)Ca(0.33)MnO(3) films (15 nm) quasicoherently grown on the (001) surface of a LaAlO(3) substrate. The films consist of single-crystal blocks with the lateral size of 30-50 nm. The atomically smooth LaAlO(3)-La(0.67)Ca(0.33)MnO(3) interphase boundary has no misfit dislocations. At T = 4.2 K, the transformation of nonferromagnetic phase inclusions into ferromagnetic ones in a constant magnetic field H is accompanied by a stable reduction in the electrical resistivity rho of manganite films with time, so that the curve rho(t) is well approximated by the relationship rho(t) similar to rho(1)(t - t (0))(1/2), (where t (0) is the time for establishment of the specified value (mu(0) H = 5 T) of the magnetic field and rho(1) is a coefficient independent of H). The magnetocrystalline anisotropy due to the elastic deformation of films by the substrate and stratification of electronic phases are the reasons of the distinct hysteresis in the dependences rho(mu(0) H, T < 100 K) obtained on mu(0) H scanning in the sequence 5 T -> 0 -> -5 T -> 0 -> 5 T. At T = 50 K and mu(0) H = 0.4 T, the magnetoresistance MR = 100% [rho(mu(0) H) - rho(mu(0) H = 0)]/rho(mu(0) H = 0) of LCMO films attains 150%.



Denna post skapades 2012-01-17. Senast ändrad 2014-11-27.
CPL Pubid: 153219

 

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Institutioner (Chalmers)

Institutionen för teknisk fysik, Mikroskopi och mikroanalys (2005-2012)
Institutionen för mikroteknologi och nanovetenskap, Kvantkomponentfysik

Ämnesområden

Fysik

Chalmers infrastruktur