High frequency magneto-electrodynamics of La_(1-x)Sr_xMnO3 single crystals

Abstract

The radio frequency (RF) response of La1-xSrxMnO3 single crystals reveal a variety of features associated with the structural, electronic and magnetic properties of the system. The resonance technique operating at ~ 4 MHz employed in this study is sensitive to small changes in both the magnetic susceptibility and resistivity of the samples. Very sharp changes in frequency are observed at the ferromagnetic (FM) and structural phase transitions in both the metallic (x = 0.175) and insulating (0.125) crystals studied. In addition to the known transitions identified as FM and orthorhombic distortions, our experiments show rich structures which are not observed in conventional DC magnetization and transport experiments. Our results demonstrate that RF experiments are ideally suited to investigate the complex phase diagram in the manganites. The colossal frequency change that we observe at the FM transition in the La1-xSrxMnO3 crystals is indicative of the enormous potential for using these materials in high frequency switching applications.