Porwal, Rajni and Pant, R. P. and Budhani, R. C.
(2015)
Magnetization dynamics in La0.67Ca0.33MnO3 epitaxial films probed with resonant and non-resonant microwave absorption.
Journal of Applied Physics, 117 (1).
013904-1-013904-7.
ISSN 0021-8979
Abstract
Temperature (T) dependent microwave absorption measurements are performed on La0.67Ca0.33MnO3 (LCMO) epitaxial thin films of thickness 100 and 200 nm in an electron paramagnetic resonance spectrometer operating in X-band. The resonant absorption peak is monitored for out-of-plane (H-perpendicular to) and in-plane (H-parallel to) dc magnetic field (H) as the system goes through magnetic ordering. These data suggest a resilient transformation to the ferromagnetic (FM) phase in the vicinity of the Curie temperature (T-C), indicative of a phase separation, which is dominant in the thinner film. The saturation magnetization is calculated from SQUID magnetometry on the same film. A pronounced zero-field absorption is seen in H-parallel to geometry displaying anomalous growth in 100 nm film at T < T-C. This feature is correlated with the magneto-conductivity of the manganite which is colossal in the vicinity of TC in the well-ordered film of thickness 200 nm. Signature of standing spin wave modes is seen in H-perpendicular to measurements which are analyzed to calculate the spin wave stiffness constant D(T) in the limit of zero temperature. The same is also inferred from the decay of equilibrium magnetization in the framework of Bloch law. These studies reveal that a bulk like LCMO is obtained in the fully relaxed thicker films.
Actions (login required)
 |
View Item |
