Giant magneto radio frequency absorption in magneto-resistive materials La{sub 0.7}(Sr,Ca){sub 0.3}MnO{sub 3}

Journal Article · Mon Sep 01 04:00:00 EDT 1997 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.366143· OSTI ID:542165

Owens, F J ^[1]

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1. Armament Research Development Center, Picatinny, New Jersey 07806 (United States)

The dc magnetic field, frequency, and temperature dependence of electromagnetic absorption at rf frequencies of 335 kHz and 10 MHz are measured in the as sintered samples of colossal magneto resistive materials La{sub 0.7}Sr{sub 0.3}MnO{sub 3} and La{sub 0.7}Ca{sub 0.3}MnO{sub 3} by measuring the penetration depth using the method of Schawlow and Devlin. Very large magneto-electromagnetic absorption effects, much larger than the magneto resistive effects, are observed. A dc magnetic field of 1000 G changes the penetration depth at 350 kHz by 53{percent} at room temperature in La{sub 0.7}Sr{sub 0.3}MnO{sub 3}, whereas the resistance of the sample only decreases by 0.75{percent} for the same field. The effects are primarily a result of the decrease of the permeability of the sample with dc magnetic field in the ferromagnetic state. A simple dc magnetometer employing the as sintered La{sub 0.7}Sr{sub 0.3}MnO{sub 3} contained in the coil of an LC oscillator as the sensing element is described.

• OSTI ID: 542165
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 6 Vol. 82; ISSN JAPIAU; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ABSORPTION SPECTRA
CALCIUM COMPOUNDS
CALCIUM OXIDES
FERROMAGNETIC MATERIALS
LANTHANUM COMPOUNDS
LANTHANUM OXIDES
MAGNETIC FIELDS
MAGNETIC SUSCEPTIBILITY
MAGNETOMETERS
MAGNETORESISTANCE
PENETRATION DEPTH
PERMEABILITY
RADIOWAVE RADIATION
STRONTIUM COMPOUNDS
STRONTIUM OXIDES
TEMPERATURE DEPENDENCE