Preparation and Properties of La_1-xA_xMnO_3 (A-Ca,Sr) Single Crystals

摘要

the method of floating zone melting with radiation heating (FZM) is widely used for growth of La_1-xA_xMnO_3 (A=Sr, Ca) single crystals. In the case of high concentration of A-elements and/or deviation of their distribution coefficient from unity the composition of floating zone changes during the growth process. As a result FZM grown crystals reveal inhomogeneous distribution of cations along the growth direction. Since the basic properties of manganites are highly sensitive to cation ratio in their crystal structure this inhomogeneity causes strong deviations of properties along the crystals obtained. In the present ork it was experimetnally shown that inhomogeneity of FZM grown crystals can be significantly reduced by using the travelling solvent floating zone method (TSFZ). Comparative data on transport properties of FZM and TSFZ grown crystals are presented.