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Title: Magnetization dynamics in La{sub 0.67}Ca{sub 0.33}MnO{sub 3} epitaxial films probed with resonant and non-resonant microwave absorption

Temperature (T) dependent microwave absorption measurements are performed on La{sub 0.67}Ca{sub 0.33}MnO{sub 3} (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{sup ⊥}) and in-plane (H{sup ∥}) 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{sub 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{sup ∥} geometry displaying anomalous growth in 100 nm film at T < T{sub C}. This feature is correlated with the magneto-conductivity of the manganite which is colossal in the vicinity of T{sub C} in the well-ordered film of thickness 200 nm. Signature of standing spin wave modes is seen in H{sup ⊥} 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 ismore » obtained in the fully relaxed thicker films.« less
Authors:
; ;  [1]
  1. National Physical Laboratory, Council of Scientific and Industrial Research, Dr K S Krishnan Marg, New Delhi-110012 (India)
Publication Date:
OSTI Identifier:
22399201
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 117; Journal Issue: 1; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ABSORPTION; CALCIUM COMPOUNDS; CURIE POINT; ELECTRON SPIN RESONANCE; EPITAXY; FERROMAGNETIC MATERIALS; FERROMAGNETISM; LANTHANUM COMPOUNDS; MAGNETIC FIELDS; MAGNETIZATION; MANGANATES; MICROWAVE RADIATION; PHASE TRANSFORMATIONS; SPIN WAVES; SQUID DEVICES; TEMPERATURE DEPENDENCE; THIN FILMS