Spin-wave resonances inLa0.7Sr0.3MnO3films: Measurement of spin-wave stiffness and anisotropy field

Abstract

We studied magnetic field dependent microwave absorption in epitaxial La 0.7 Sr 0.3 MnO 3 films using an X-band Bruker ESR spectrometer. By analyzing angular and temperature dependence of the ferromagnetic and spin-wave resonances we determine spin-wave stiffness and anisotropy field.The spin-wave stiffness as found from the spectrum of the standing spin-wave resonances in thin films is in fair agreement with the results of inelastic neutron scattering studies on a single crystal of the same composition [Vasiliu-Doloc et al., J. Appl. Phys. 83, 7343 (1998)].

Temperature dependence of magnetic properties ofLa0.7Sr0.3MnO3/SrTiO

“…10,14 Notice that its sign depends on the sign of the mismatch between the lattice constants of La 0.7 Sr 0.3 MnO 3 and the substrate; it was found positive in the case of LaAlO 3 ͑compressive strain͒ 14 but it is negative in the case of STO ͑extensive strain͒. 10 The temperature variation in the fourfold in-plane anisotropy field was also studied and it is shown in Fig. 9͑a͒; in both films the easy axis remains along the ͓110͔ direction ͑i.e., 4 = 45°and H 4 Ͼ 0͒.…”

“…Figure 8͑b͒ presents the resulting temperature variation in ͉K Ќ ͉; in both samples it approximately linearly decreases above 120 K from about 1.5 ϫ 10 6 erg/ cm 3 down to 2.5ϫ 10 5 erg/ cm 3 at 300 K. Large negative values of K Ќ have been observed previously in La 0.7 Sr 0.3 MnO 3 films grown on a SrTiO 3 substrate. 10 The main source of uniaxial perpendicular anisotropy is generally considered as proceeding from the interfacial strain through the magnetoelastic coupling. 10,14 Notice that its sign depends on the sign of the mismatch between the lattice constants of La 0.7 Sr 0.3 MnO 3 and the substrate; it was found positive in the case of LaAlO 3 ͑compressive strain͒ 14 but it is negative in the case of STO ͑extensive strain͒.…”

“…10 The main source of uniaxial perpendicular anisotropy is generally considered as proceeding from the interfacial strain through the magnetoelastic coupling. 10,14 Notice that its sign depends on the sign of the mismatch between the lattice constants of La 0.7 Sr 0.3 MnO 3 and the substrate; it was found positive in the case of LaAlO 3 ͑compressive strain͒ 14 but it is negative in the case of STO ͑extensive strain͒. 10 The temperature variation in the fourfold in-plane anisotropy field was also studied and it is shown in Fig.…”

Twinned-domain-induced magnonic modes in epitaxial LSMO/STO films

“…LSMO is the most widely studied of the manganese oxides due to itshigh Curie temperature (bulk » T 370 C K), a high degree of spin polarization [18,19], and the existence of the colossal magnetoresistive effect [20]. Prior investigations of LSMO thin films indicate that it hasrelatively low magnetodynamic damping [21][22][23], which isone of the prerequisites for use in devices. Bulk LSMO has a rhombohedral unit cell that slightly deviates from the cubic unit cell of the (001) surface of an STO substrate.…”

“…where D is the temperature-dependent spin wave stiffness obtained from the literature [21]. In the y-direction, m=0 since this direction does not display structural periodicity.…”