Spin dependent distribution and Fermi surface of the perovskite manganite compound La0.7Sr0.3MnO3 via 2D-ACAR measurements

Using 2D angular correlation of positron annihilation radiation (ACAR) experiment, we have performed a systematic study of the spin dependent and Fermi surface of the colossal magneto-resistance CMR La0.7Sr0.3MnO3. The measurements have been carried out using a reversal magnetic field direction (parallel and anti-parallel to the direction of motion of the polarized positrons). The measured spectra have been investigated in the momentum space as well as in the wave vector space. They revealed information about the hybridization effect of Mn(3 d e(g)(1)) and O(2p) like states. Further, the results showed that the majority spin electrons predominated at the Fermi level. From another perspective, the Fermi surface of La0.7Sr0.3MnO3 revealed a cuboids hole surface centered on R point and a spheroid electron surface centered on Gamma point. A comparison with the earlier results showed qualitative agreement. However, the current results could reveal the dimension of the electron surface centered on Gamma point that was predicted in the earlier 2D-ACAR measurements. (C) 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.