Absorption of microwaves in La1−xSrxMnO3 manganese powders over a wide bandwidth

Abstract

We present the frequency dependence of microwave-absorbing properties of La 1Ϫx Sr x MnO 3 ͑xϭ0.4, 0.5, 0.6, and 0.7͒ powders at room temperature. The absorbing properties change gradually with x in the frequency range of 8-12 GHz. The optimal absorption can be achieved for a xϭ0.4 sample and its microwave loss peak value is about 25 dB. Further experimental results show that the absorption can be attributed to magnetic and dielectric losses and the microwave loss peak corresponds to the maximum dielectric loss tangent tan ␦ e near 10.5 GHz. Furthermore, the absorbing properties of the oxides mixed with carbonic fiber and Y-type planar hexagonal ferrite have been rudimentarily studied. Results show that these additives greatly enhance the microwave-absorbing properties of the oxides.

Synthesis and microwave absorption properties of FeCo nanoplates

“…Commonly, microwave absorption is determined by both dielectric loss and magnetic loss [33]. In order to examine which one dominates the loss for the FeCo nanoplates, dielectric loss factor (tan ı e = ε /ε ) and magnetic loss factor (tan ı m = / ) are calculated.…”

MICROWAVE ABSORPTION, CONDUCTIVITY AND COMPLEX PEMITTIVITY OF FRITLESS Ni(1-x)CuxMn2O4 (0≤x≤1) CERAMIC THICK FILM:EFFECT OF COPPER

“…where, V T is transmitted output power by thick film, V I is the incident power on thick film. [17]. Absorption is the heat loss under the action between electric dipole or magnetic dipole in material and the electromagnetic field.…”

Crystal microstructure, infrared absorption, and microwave electromagnetic properties of (La1−x Dy x )2/3Sr1/3MnO3

“…They thought that the microwave absorption in La 0.7 Sr 0.3 MnO 3 was in connection with ferromagnetism. Li et al [17] surveyed the microwave absorption properties of La 1-x Sr x MnO 3 (x = 0.4, 0.5, 0.6, and 0.7); they thought that the absorption loss included both magnetic and dielectric losses. Our measurements indicate that La with a large radius and non-magnetism partially substituted by Dy with a small radius but strong magnetic moment in La 2/3 Sr 1/3 MnO 3 makes the microwave absorption mechanism to be more complicated than that of the undoped.…”