钙钛矿型锰氧化物La0.7Sr0.3MnO3的磁谱研究

报导了钙钛矿型锰氧化物La0.7Sr0.3MnO3多晶体材料不同温度下磁谱的初步研究结果，平均粒径分别为45、66、105、140和1200nm的样品由溶胶－凝胶法制备，当平均粒径大于105nm时，样品的磁谱为典型的预豫型谱线，共振频率和准静态磁导率随温度降低而减少；随平均粒径增加，准记磁导率增大，而共振频率却减小，当平均粒径小于66nm时，观察不到类似的驰豫，实验结果显示，驰豫谱线主要是由于畴壁位移造成的，而畴壁位移的阻尼主要是与畴壁位移相联系的微观涡流效应。

Magnetic Spectra Investigations of Granular Perovskite La0.7Sr0.3MnO3

The preliminary investigations about the magnetic spectra of perovskite La 0.7Sr 0.3MnO 3 have been carried out. The samples with average grain size (D) of 45, 66,105,140 and 1 200 nm are fabricated using sol-gel technique. The spectra resemble a relaxation character when D is larger than 105 nm. The static permeability and resonance frequency decrease with the drop of temperature. With increasing D the static permeability increases and the resonance frequency reduces. No relaxation can be observed when D is smaller than 66 nm. The relaxations are attributed to the displacements of domain walls, and the damping primarily originates from the effect of microscopic eddy current associated with wall motions.