Laser-diode-heated floating zone (LDFZ) method appropriate to crystal growth of incongruently melting materials

TL;DR

The paper introduces the LDFZ method, a laser-diode-based technique that improves homogeneous heating for crystal growth of incongruently melting materials, demonstrating enhanced stability and reproducibility.

Contribution

It presents a novel laser-diode-heated floating zone method with simulation, design, and successful application to difficult-to-grow incongruently melting crystals.

Findings

Successful growth of BiFeO3 and (La,Ba)2CuO4 crystals

Enhanced homogeneity and stability in crystal growth

Tolerance to sample decentering and efficient heating

Abstract

We have developed the laser-diode-heated floating zone (LDFZ) method, in order to improve the broad and inhomogeneous light focusing in the conventional lamp-heated floating zone method, which often causes difficulties in the crystal growth especially for the incongruently melting materials. We have simulated the light focusing properties of the LDFZ method to make irradiated light homogeneous and restricted mostly to the molten zone. We have designed and assembled an LDFZ furnace, and have demonstrated how it works through actual crystal growth. The method is applicable to various kinds of materials, and enables stable and reproducible crystal growth even for the incongruently melting materials. We have succeeded in the crystal growth of representative incongruently melting materials such as BiFeO3 and (La,Ba)2CuO4, which are difficult to grow by the conventional method. Tolerance to the decentering of the sample and highly efficient heating are also established in the LDFZ method.